1. Definition of Work in Physics: - Work is defined as the product of force and displacement in the direction of the force applied. 2. Force Exerted by the Person: - The person exerts a force against gravity to hold the bundle of hay over his head, countering the weight of the hay. 3. Absence of DisRead more
1. Definition of Work in Physics:
– Work is defined as the product of force and displacement in the direction of the force applied.
2. Force Exerted by the Person:
– The person exerts a force against gravity to hold the bundle of hay over his head, countering the weight of the hay.
3. Absence of Displacement:
– Despite exerting a force to hold the bundle, there is no vertical displacement or change in the position of the hay during the 30 minutes.
– The bundle of hay remains stationary and does not move vertically while being held.
4. Work Calculation Criteria:
– For work to be done, there must be a displacement in the direction of the force applied.
– Work is calculated as W = F x d x cos(θ), where F is force, (d) is displacement, and (θ) is the angle between force and displacement.
5. No Displacement, No Work Done:
– In this scenario, although the person exerts a force to counteract gravity, there is no vertical movement or displacement of the hay.
– The absence of vertical displacement means that the force applied by the person does not result in any work being done on the bundle of hay.
6. Explanation of Fatigue:
– The person may feel tired due to muscular effort expended to maintain the position of the hay against gravity for an extended period.
– However, the fatigue is not due to the performance of physical work in the physics sense as there is no displacement in the direction of the force applied.
1. Power Rating of the Electric Heater: - The power rating of the electric heater is 1500 watts (W). 2. Time Duration: - The time duration for which we want to calculate the energy used is 10 hours. 3. Formula for Energy Calculation: - The formula to calculate energy (in joules) is: Energy = Power ×Read more
1. Power Rating of the Electric Heater:
– The power rating of the electric heater is 1500 watts (W).
2. Time Duration:
– The time duration for which we want to calculate the energy used is 10 hours.
3. Formula for Energy Calculation:
– The formula to calculate energy (in joules) is: Energy = Power × Time
4. Conversion of Time:
– Convert the time duration from hours to seconds because the power is given in watts.
– 10 hours = 10 x 60 x 60 seconds = 36,000 seconds
5. Calculation of Energy Used:
– Energy Used = Power × Time
– Energy Used = 1500 W x 36,000 s
– Energy Used = 54,000,000 J
6. Conversion to Kilowatt-Hours (Optional):
– To express energy in kilowatt-hours (kWh), divide the energy in joules by 3.6 x 10⁶ (since 1 kWh = 3.6 x 10⁶ J).
– Energy Used in kWh = (54,000,000 J)/(3.6 x 10⁶ J/kWh)
– Energy Used in kWh = 15 kWh
Therefore, the electric heater rated at 1500 W will consume 54,000,000 joules of energy or 15 kilowatt-hours of energy in 10 hours of operation.
1. Initial Energy States: - Potential Energy: When the pendulum bob is drawn to one side, it gains potential energy due to its height above the equilibrium position. - Kinetic Energy: Initially, the pendulum bob is at rest, so it possesses zero kinetic energy. 2. Conversion of Potential to Kinetic ERead more
1. Initial Energy States:
– Potential Energy: When the pendulum bob is drawn to one side, it gains potential energy due to its height above the equilibrium position.
– Kinetic Energy: Initially, the pendulum bob is at rest, so it possesses zero kinetic energy.
2. Conversion of Potential to Kinetic Energy:
– As the pendulum swings downward, potential energy converts into kinetic energy. At the lowest point of the swing, all potential energy is converted to kinetic energy.
– The pendulum reaches its maximum kinetic energy at the bottom of the swing, moving at its maximum speed.
3. Oscillation and Energy Transformation:
– The pendulum continues to oscillate, with energy continuously transforming between potential and kinetic forms as it swings back and forth.
4. Energy Dissipation:
– Factors like air resistance, friction at the pivot, and internal friction cause the pendulum to lose energy gradually.
– The lost energy transforms into less usable forms such as heat and sound, dissipating into the surroundings.
5. Decrease in Amplitude:
– As energy dissipates, the pendulum’s amplitude (maximum swing angle) decreases gradually with each swing.
– Eventually, due to energy losses, the pendulum comes to rest at its equilibrium position.
6. Conservation of Total Energy:
– While the pendulum eventually stops moving, the total energy of the system (including the pendulum and its surroundings) remains constant.
– Energy is not lost but rather transformed into less available forms, conforming to the law of conservation of energy.
7. Energy Transformation Summary:
– Initial potential energy is converted to kinetic energy during the swing.
– Energy dissipates due to various factors, leading to a decrease in motion until the pendulum eventually comes to rest.
– The total energy within the system and surroundings remains conserved, even though it becomes less available for useful work due to dissipation.
To bring an object of mass (m) and constant velocity (v) to rest, we need to reduce its kinetic energy to zero. The work (W) done on an object is equal to the change in its kinetic energy. The kinetic energy (KE) of an object moving with velocity (v) is given by: KE = 1/2 mv² When the object is brouRead more
To bring an object of mass (m) and constant velocity (v) to rest, we need to reduce its kinetic energy to zero.
The work (W) done on an object is equal to the change in its kinetic energy. The kinetic energy (KE) of an object moving with velocity (v) is given by:
KE = 1/2 mv²
When the object is brought to rest, its final kinetic energy (KE_final) will be zero.
The initial kinetic energy (KE_initial) of the object moving with velocity (v) is 1/2 mv²).
Therefore, the work done to bring the object to rest is:
W = KE_final – KE_initial = 0 – 1/2} m v² = – 1/2 m v²
Hence, to bring an object of mass (m) moving with constant velocity (v) to rest, a total amount of work equal to ( -1/2 m v²) needs to be done on the object. The negative sign indicates that work is done against the object’s motion to reduce its kinetic energy to zero.
Given: - Mass of the car, m = 1500 kg - Initial velocity of the car, v = 60 km/h 1. Convert Velocity to Meters per Second: - Velocity in meters per second = (Velocity in km/h x 1000)/(3600) - 60 km/h = (60 x 1000)/(3600} = 16.67 m/s 2. Calculate Initial Kinetic Energy: - The kinetic energy (KE) of tRead more
Given:
– Mass of the car, m = 1500 kg
– Initial velocity of the car, v = 60 km/h
1. Convert Velocity to Meters per Second:
– Velocity in meters per second = (Velocity in km/h x 1000)/(3600)
– 60 km/h = (60 x 1000)/(3600} = 16.67 m/s
2. Calculate Initial Kinetic Energy:
– The kinetic energy (KE) of the car is given by KE = 1/2 m v² .
– Substitute the values:
KE = 1/2 x 1500 kg x (16.67 m/s²)
– KE = 208,333.33 J
3. Determine Work Required:
– The work (W) needed to stop the car is equal to the change in kinetic energy.
– W = Initial Kinetic Energy – Final Kinetic Energy)
– As the final kinetic energy is zero (when the car is brought to rest), ( W = 208,333.33 J – 0J = 208,333.33 J
Therefore, the work required to stop the car of 1500 kg moving at a velocity of 60 km/h is (208,333.33 J). This amount of work needs to be done to reduce the car’s kinetic energy to zero, bringing it to a complete stop.
1. Newton's Second Law: - Newton's Second Law of Motion states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass (F = ma). 2. Forces in Equilibrium: - When multiple forces act on an object simultaneously, their combined eRead more
1. Newton’s Second Law:
– Newton’s Second Law of Motion states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass (F = ma).
2. Forces in Equilibrium:
– When multiple forces act on an object simultaneously, their combined effect determines the object’s acceleration.
– If the forces are balanced or cancel each other out, resulting in a net force of zero, the object is in a state of equilibrium.
3. Zero Net Force, Zero Acceleration:
– In a state of equilibrium where the net force is zero, according to Newton’s Second Law, the acceleration of the object will be zero, regardless of the number of forces acting on it.
– Balanced forces prevent any change in the object’s motion, maintaining either rest or constant velocity (zero acceleration).
4. Examples of Equilibrium:
– An object at rest on a surface experiences forces like gravity pulling it downward and the normal force from the surface pushing upward. If these forces are equal in magnitude and opposite in direction, the object remains stationary with zero acceleration.
– Similarly, an object moving at a constant velocity experiences balanced forces, resulting in zero net force and zero acceleration despite multiple forces acting on it.
5. Conclusion:
– Zero acceleration is possible when the forces acting on an object are in equilibrium, canceling each other out and resulting in a net force of zero according to Newton’s Second Law.
Therefore, I concur with Soni that an object can have zero acceleration even when several forces are acting on it if these forces are balanced and create a state of equilibrium where the net force on the object is zero. This state prevents any change in the object’s motion, leading to zero acceleration.
Energy = Power x Time Given that each device has a power of 500 W and the time duration is 10 hours, let's calculate the total energy consumed by all four devices: Total power of four devices = 4 x 500 W = 2000 W Time = 10 hours Now, to find the energy consumed: Energy = Total Power x Time Energy =Read more
Energy = Power x Time
Given that each device has a power of 500 W and the time duration is 10 hours, let’s calculate the total energy consumed by all four devices:
Total power of four devices = 4 x 500 W = 2000 W
Time = 10 hours
Now, to find the energy consumed:
Energy = Total Power x Time
Energy = 2000 W x 10 h
Let’s calculate:
Energy = 20,000 Wh
To convert watt-hours (Wh) to kilowatt-hours (kWh), we divide by 1000:
Energy = (20,000 Wh)/(1000) = 20 kWh
Therefore, the total energy consumed by the four devices in 10 hours is 20 kilowatt-hours (kWh).
The key points regarding what happens to the kinetic energy of a freely falling object when it eventually stops upon reaching the ground: 1. Initial Kinetic Energy: The object gains kinetic energy as it falls due to its motion and the force of gravity acting on it. 2. Transformation upon Impact: WheRead more
The key points regarding what happens to the kinetic energy of a freely falling object when it eventually stops upon reaching the ground:
1. Initial Kinetic Energy: The object gains kinetic energy as it falls due to its motion and the force of gravity acting on it.
2. Transformation upon Impact: When the object reaches the ground and comes to a stop, its kinetic energy is not lost but transformed into other forms of energy.
3. Heat Energy: Some of the object’s kinetic energy is converted into heat energy upon impact due to friction between the object and the surface it lands on.
4. Sound Energy: Part of the object’s kinetic energy is transformed into sound energy upon impact, generating sound waves due to the collision.
5. Deformation or Potential Energy: Depending on the characteristics of the object and the surface it lands on, the kinetic energy might also cause deformation or compression, storing potential energy within the object or the ground.
6. Conclusion: In summary, the kinetic energy of a freely falling object, when it stops upon reaching the ground, is not eliminated but rather converted into different forms of energy such as heat, sound, or potential energy associated with deformation.
1. Chemical Energy Conversion: - The battery stores chemical energy within its cells. - A chemical reaction inside the battery converts stored chemical energy into electrical energy. 2. Electrical Energy Transfer: - Electrical energy generated by the battery flows through the circuit wires toward thRead more
1. Chemical Energy Conversion:
– The battery stores chemical energy within its cells.
– A chemical reaction inside the battery converts stored chemical energy into electrical energy.
2. Electrical Energy Transfer:
– Electrical energy generated by the battery flows through the circuit wires toward the bulb.
– The energy is in the form of moving electrons within the wires.
3. Transformation in the Bulb:
– Electrical energy reaches the bulb’s components, such as the filament.
– The bulb’s filament, offering resistance, converts electrical energy into thermal energy and light energy.
4. Light and Heat Emission:
– Light energy is emitted as the filament heats up, producing visible light.
– Heat energy is also generated due to the high temperature of the filament.
5. Energy Loss:
– Not all electrical energy is transformed into light and heat. Some is lost as heat due to resistance in wires and components.
– Energy dissipates as heat, warming the surroundings.
Understanding these energy changes highlights the transformation of stored chemical energy in the battery into electrical energy, and subsequently into light and heat energy within the bulb, demonstrating the various forms of energy conversion and dissipation in the process of lighting a bulb using a battery.
Given: - Mass (m) = 20 kg - Initial velocity (v_initial) = 5 m/s - Final velocity (v_final) = 2 m/s 1. Work-Energy Principle: - The work done (W) on an object is equal to the change in its kinetic energy (Δ KE). 2. Change in Kinetic Energy: - The change in kinetic energy (Δ KE) formula is: Δ KE = 1/Read more
Given:
– Mass (m) = 20 kg
– Initial velocity (v_initial) = 5 m/s
– Final velocity (v_final) = 2 m/s
1. Work-Energy Principle:
– The work done (W) on an object is equal to the change in its kinetic energy (Δ KE).
2. Change in Kinetic Energy:
– The change in kinetic energy (Δ KE) formula is:
Δ KE = 1/2 x m x ( v²_final – v²_initial)
3. Calculation:
– Substituting the given values into the formula:
Δ KE = 1/2 x 20 kg x (2 m/s)² – (5 m/s)²
Δ KE = -210J
4. Result and Interpretation:
– The change in kinetic energy is -210 J
– Since work done is equal to the change in kinetic energy, the work done by the force is also -210 J
– The negative sign indicates that the work done by the force results in a decrease in the object’s kinetic energy.
Understanding these steps illustrates how the work done by a force can be calculated using the change in kinetic energy, providing insight into the change in energy associated with the object’s changing velocities due to the force applied.
A person holds a bundle of hay over his head for 30 minutes and gets tired. Has he done some work or not? Justify your answer.
1. Definition of Work in Physics: - Work is defined as the product of force and displacement in the direction of the force applied. 2. Force Exerted by the Person: - The person exerts a force against gravity to hold the bundle of hay over his head, countering the weight of the hay. 3. Absence of DisRead more
1. Definition of Work in Physics:
– Work is defined as the product of force and displacement in the direction of the force applied.
2. Force Exerted by the Person:
– The person exerts a force against gravity to hold the bundle of hay over his head, countering the weight of the hay.
3. Absence of Displacement:
– Despite exerting a force to hold the bundle, there is no vertical displacement or change in the position of the hay during the 30 minutes.
– The bundle of hay remains stationary and does not move vertically while being held.
4. Work Calculation Criteria:
– For work to be done, there must be a displacement in the direction of the force applied.
– Work is calculated as W = F x d x cos(θ), where F is force, (d) is displacement, and (θ) is the angle between force and displacement.
5. No Displacement, No Work Done:
– In this scenario, although the person exerts a force to counteract gravity, there is no vertical movement or displacement of the hay.
– The absence of vertical displacement means that the force applied by the person does not result in any work being done on the bundle of hay.
6. Explanation of Fatigue:
See less– The person may feel tired due to muscular effort expended to maintain the position of the hay against gravity for an extended period.
– However, the fatigue is not due to the performance of physical work in the physics sense as there is no displacement in the direction of the force applied.
An electric heater is rated 1500 W. How much energy does it use in 10 hours?
1. Power Rating of the Electric Heater: - The power rating of the electric heater is 1500 watts (W). 2. Time Duration: - The time duration for which we want to calculate the energy used is 10 hours. 3. Formula for Energy Calculation: - The formula to calculate energy (in joules) is: Energy = Power ×Read more
1. Power Rating of the Electric Heater:
– The power rating of the electric heater is 1500 watts (W).
2. Time Duration:
– The time duration for which we want to calculate the energy used is 10 hours.
3. Formula for Energy Calculation:
– The formula to calculate energy (in joules) is: Energy = Power × Time
4. Conversion of Time:
– Convert the time duration from hours to seconds because the power is given in watts.
– 10 hours = 10 x 60 x 60 seconds = 36,000 seconds
5. Calculation of Energy Used:
– Energy Used = Power × Time
– Energy Used = 1500 W x 36,000 s
– Energy Used = 54,000,000 J
6. Conversion to Kilowatt-Hours (Optional):
– To express energy in kilowatt-hours (kWh), divide the energy in joules by 3.6 x 10⁶ (since 1 kWh = 3.6 x 10⁶ J).
– Energy Used in kWh = (54,000,000 J)/(3.6 x 10⁶ J/kWh)
– Energy Used in kWh = 15 kWh
Therefore, the electric heater rated at 1500 W will consume 54,000,000 joules of energy or 15 kilowatt-hours of energy in 10 hours of operation.
See lessIllustrate the law of conservation of energy by discussing the energy changes which occur when we draw a pendulum bob to one side and allow it to oscillate. Why does the bob eventually come to rest? What happens to its energy eventually? Is it a violation of the law of conservation of energy?
1. Initial Energy States: - Potential Energy: When the pendulum bob is drawn to one side, it gains potential energy due to its height above the equilibrium position. - Kinetic Energy: Initially, the pendulum bob is at rest, so it possesses zero kinetic energy. 2. Conversion of Potential to Kinetic ERead more
1. Initial Energy States:
– Potential Energy: When the pendulum bob is drawn to one side, it gains potential energy due to its height above the equilibrium position.
– Kinetic Energy: Initially, the pendulum bob is at rest, so it possesses zero kinetic energy.
2. Conversion of Potential to Kinetic Energy:
– As the pendulum swings downward, potential energy converts into kinetic energy. At the lowest point of the swing, all potential energy is converted to kinetic energy.
– The pendulum reaches its maximum kinetic energy at the bottom of the swing, moving at its maximum speed.
3. Oscillation and Energy Transformation:
– The pendulum continues to oscillate, with energy continuously transforming between potential and kinetic forms as it swings back and forth.
4. Energy Dissipation:
– Factors like air resistance, friction at the pivot, and internal friction cause the pendulum to lose energy gradually.
– The lost energy transforms into less usable forms such as heat and sound, dissipating into the surroundings.
5. Decrease in Amplitude:
– As energy dissipates, the pendulum’s amplitude (maximum swing angle) decreases gradually with each swing.
– Eventually, due to energy losses, the pendulum comes to rest at its equilibrium position.
6. Conservation of Total Energy:
– While the pendulum eventually stops moving, the total energy of the system (including the pendulum and its surroundings) remains constant.
– Energy is not lost but rather transformed into less available forms, conforming to the law of conservation of energy.
7. Energy Transformation Summary:
See less– Initial potential energy is converted to kinetic energy during the swing.
– Energy dissipates due to various factors, leading to a decrease in motion until the pendulum eventually comes to rest.
– The total energy within the system and surroundings remains conserved, even though it becomes less available for useful work due to dissipation.
An object of mass, m is moving with a constant velocity, v. How much work should be done on the object in order to bring the object to rest?
To bring an object of mass (m) and constant velocity (v) to rest, we need to reduce its kinetic energy to zero. The work (W) done on an object is equal to the change in its kinetic energy. The kinetic energy (KE) of an object moving with velocity (v) is given by: KE = 1/2 mv² When the object is brouRead more
To bring an object of mass (m) and constant velocity (v) to rest, we need to reduce its kinetic energy to zero.
The work (W) done on an object is equal to the change in its kinetic energy. The kinetic energy (KE) of an object moving with velocity (v) is given by:
KE = 1/2 mv²
When the object is brought to rest, its final kinetic energy (KE_final) will be zero.
The initial kinetic energy (KE_initial) of the object moving with velocity (v) is 1/2 mv²).
Therefore, the work done to bring the object to rest is:
W = KE_final – KE_initial = 0 – 1/2} m v² = – 1/2 m v²
Hence, to bring an object of mass (m) moving with constant velocity (v) to rest, a total amount of work equal to ( -1/2 m v²) needs to be done on the object. The negative sign indicates that work is done against the object’s motion to reduce its kinetic energy to zero.
See lessCalculate the work required to be done to stop a car of 1500 kg moving at a velocity of 60 km/h?
Given: - Mass of the car, m = 1500 kg - Initial velocity of the car, v = 60 km/h 1. Convert Velocity to Meters per Second: - Velocity in meters per second = (Velocity in km/h x 1000)/(3600) - 60 km/h = (60 x 1000)/(3600} = 16.67 m/s 2. Calculate Initial Kinetic Energy: - The kinetic energy (KE) of tRead more
Given:
– Mass of the car, m = 1500 kg
– Initial velocity of the car, v = 60 km/h
1. Convert Velocity to Meters per Second:
– Velocity in meters per second = (Velocity in km/h x 1000)/(3600)
– 60 km/h = (60 x 1000)/(3600} = 16.67 m/s
2. Calculate Initial Kinetic Energy:
– The kinetic energy (KE) of the car is given by KE = 1/2 m v² .
– Substitute the values:
KE = 1/2 x 1500 kg x (16.67 m/s²)
– KE = 208,333.33 J
3. Determine Work Required:
– The work (W) needed to stop the car is equal to the change in kinetic energy.
– W = Initial Kinetic Energy – Final Kinetic Energy)
– As the final kinetic energy is zero (when the car is brought to rest), ( W = 208,333.33 J – 0J = 208,333.33 J
Therefore, the work required to stop the car of 1500 kg moving at a velocity of 60 km/h is (208,333.33 J). This amount of work needs to be done to reduce the car’s kinetic energy to zero, bringing it to a complete stop.
See lessSoni says that the acceleration in an object could be zero even when several forces are acting on it. Do you agree with her? Why?
1. Newton's Second Law: - Newton's Second Law of Motion states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass (F = ma). 2. Forces in Equilibrium: - When multiple forces act on an object simultaneously, their combined eRead more
1. Newton’s Second Law:
– Newton’s Second Law of Motion states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass (F = ma).
2. Forces in Equilibrium:
– When multiple forces act on an object simultaneously, their combined effect determines the object’s acceleration.
– If the forces are balanced or cancel each other out, resulting in a net force of zero, the object is in a state of equilibrium.
3. Zero Net Force, Zero Acceleration:
– In a state of equilibrium where the net force is zero, according to Newton’s Second Law, the acceleration of the object will be zero, regardless of the number of forces acting on it.
– Balanced forces prevent any change in the object’s motion, maintaining either rest or constant velocity (zero acceleration).
4. Examples of Equilibrium:
– An object at rest on a surface experiences forces like gravity pulling it downward and the normal force from the surface pushing upward. If these forces are equal in magnitude and opposite in direction, the object remains stationary with zero acceleration.
– Similarly, an object moving at a constant velocity experiences balanced forces, resulting in zero net force and zero acceleration despite multiple forces acting on it.
5. Conclusion:
– Zero acceleration is possible when the forces acting on an object are in equilibrium, canceling each other out and resulting in a net force of zero according to Newton’s Second Law.
Therefore, I concur with Soni that an object can have zero acceleration even when several forces are acting on it if these forces are balanced and create a state of equilibrium where the net force on the object is zero. This state prevents any change in the object’s motion, leading to zero acceleration.
See lessFind the energy in kW h consumed in 10 hours by four devices of power 500 W each.
Energy = Power x Time Given that each device has a power of 500 W and the time duration is 10 hours, let's calculate the total energy consumed by all four devices: Total power of four devices = 4 x 500 W = 2000 W Time = 10 hours Now, to find the energy consumed: Energy = Total Power x Time Energy =Read more
Energy = Power x Time
Given that each device has a power of 500 W and the time duration is 10 hours, let’s calculate the total energy consumed by all four devices:
Total power of four devices = 4 x 500 W = 2000 W
Time = 10 hours
Now, to find the energy consumed:
Energy = Total Power x Time
Energy = 2000 W x 10 h
Let’s calculate:
Energy = 20,000 Wh
To convert watt-hours (Wh) to kilowatt-hours (kWh), we divide by 1000:
Energy = (20,000 Wh)/(1000) = 20 kWh
Therefore, the total energy consumed by the four devices in 10 hours is 20 kilowatt-hours (kWh).
See lessA freely falling object eventually stops on reaching the ground. What happenes to its kinetic energy?
The key points regarding what happens to the kinetic energy of a freely falling object when it eventually stops upon reaching the ground: 1. Initial Kinetic Energy: The object gains kinetic energy as it falls due to its motion and the force of gravity acting on it. 2. Transformation upon Impact: WheRead more
The key points regarding what happens to the kinetic energy of a freely falling object when it eventually stops upon reaching the ground:
1. Initial Kinetic Energy: The object gains kinetic energy as it falls due to its motion and the force of gravity acting on it.
2. Transformation upon Impact: When the object reaches the ground and comes to a stop, its kinetic energy is not lost but transformed into other forms of energy.
3. Heat Energy: Some of the object’s kinetic energy is converted into heat energy upon impact due to friction between the object and the surface it lands on.
4. Sound Energy: Part of the object’s kinetic energy is transformed into sound energy upon impact, generating sound waves due to the collision.
5. Deformation or Potential Energy: Depending on the characteristics of the object and the surface it lands on, the kinetic energy might also cause deformation or compression, storing potential energy within the object or the ground.
6. Conclusion: In summary, the kinetic energy of a freely falling object, when it stops upon reaching the ground, is not eliminated but rather converted into different forms of energy such as heat, sound, or potential energy associated with deformation.
See lessA battery lights a bulb. Describe the energy changes involved in the process.
1. Chemical Energy Conversion: - The battery stores chemical energy within its cells. - A chemical reaction inside the battery converts stored chemical energy into electrical energy. 2. Electrical Energy Transfer: - Electrical energy generated by the battery flows through the circuit wires toward thRead more
1. Chemical Energy Conversion:
– The battery stores chemical energy within its cells.
– A chemical reaction inside the battery converts stored chemical energy into electrical energy.
2. Electrical Energy Transfer:
– Electrical energy generated by the battery flows through the circuit wires toward the bulb.
– The energy is in the form of moving electrons within the wires.
3. Transformation in the Bulb:
– Electrical energy reaches the bulb’s components, such as the filament.
– The bulb’s filament, offering resistance, converts electrical energy into thermal energy and light energy.
4. Light and Heat Emission:
– Light energy is emitted as the filament heats up, producing visible light.
– Heat energy is also generated due to the high temperature of the filament.
5. Energy Loss:
– Not all electrical energy is transformed into light and heat. Some is lost as heat due to resistance in wires and components.
– Energy dissipates as heat, warming the surroundings.
Understanding these energy changes highlights the transformation of stored chemical energy in the battery into electrical energy, and subsequently into light and heat energy within the bulb, demonstrating the various forms of energy conversion and dissipation in the process of lighting a bulb using a battery.
See lessCertain force acting on a 20 kg mass changes its velocity from 5 m s^–1 to 2 m s^–1. Calculate the work done by the force.
Given: - Mass (m) = 20 kg - Initial velocity (v_initial) = 5 m/s - Final velocity (v_final) = 2 m/s 1. Work-Energy Principle: - The work done (W) on an object is equal to the change in its kinetic energy (Δ KE). 2. Change in Kinetic Energy: - The change in kinetic energy (Δ KE) formula is: Δ KE = 1/Read more
Given:
– Mass (m) = 20 kg
– Initial velocity (v_initial) = 5 m/s
– Final velocity (v_final) = 2 m/s
1. Work-Energy Principle:
– The work done (W) on an object is equal to the change in its kinetic energy (Δ KE).
2. Change in Kinetic Energy:
– The change in kinetic energy (Δ KE) formula is:
Δ KE = 1/2 x m x ( v²_final – v²_initial)
3. Calculation:
– Substituting the given values into the formula:
Δ KE = 1/2 x 20 kg x (2 m/s)² – (5 m/s)²
Δ KE = -210J
4. Result and Interpretation:
– The change in kinetic energy is -210 J
– Since work done is equal to the change in kinetic energy, the work done by the force is also -210 J
– The negative sign indicates that the work done by the force results in a decrease in the object’s kinetic energy.
Understanding these steps illustrates how the work done by a force can be calculated using the change in kinetic energy, providing insight into the change in energy associated with the object’s changing velocities due to the force applied.
See less