Due to the backward reaction of the water being ejected When a fireman holds a hose, which is ejecting large amounts of water at a high velocity, then a reaction force is exerted on him by the ejecting water in the backward direction. This is because of Newton's third law of motion. As a result of tRead more
Due to the backward reaction of the water being ejected
When a fireman holds a hose, which is ejecting large amounts of water at a high velocity, then a reaction force is exerted on him by the ejecting water in the backward direction. This is because of Newton’s third law of motion. As a result of the backward force, the stability of the fireman decreases.
Hence, it is difficult for him to remain stable while holding the hose.
A horse pushes the ground in the backward direction. According to Newton's third law of motion, a reaction force is exerted by the Earth on the horse in the forward direction. As a result, the cart moves forward. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-Read more
A horse pushes the ground in the backward direction. According to Newton’s third law of motion, a reaction force is exerted by the Earth on the horse in the forward direction. As a result, the cart moves forward.
Due to the inertia of the passenger Everybody tries to maintain its state of motion or state of rest. If a body is at rest, then it tries to remain at rest. If a body is moving, then it tries to remain in motion. In a moving bus, a passenger moves with the bus. As the driver applies brakes, the busRead more
Due to the inertia of the passenger
Everybody tries to maintain its state of motion or state of rest. If a body is at rest, then it tries to remain at rest. If a body is moving, then it tries to remain in motion. In a moving bus, a passenger moves with the bus. As the driver applies brakes, the bus comes to rest. But, the passenger tries to maintain his state of motion. As a result, a forward force is exerted on him.
Similarly, the passenger tends to fall backwards when the bus accelerates from rest. This is because when the bus accelerates, the inertia of the passenger tends to oppose the forward motion of the bus. Hence, the passenger tends to fall backwards when the bus accelerates forward.
Some leaves of a tree get detached when we shake its branches vigorously. This is because when the branches of a tree are shaken, it moves to and fro, but its leaves tend to remain at rest. This is because the inertia of the leaves tend to resist the to and fro motion. Due to this reason, the leavesRead more
Some leaves of a tree get detached when we shake its branches vigorously. This is because when the branches of a tree are shaken, it moves to and fro, but its leaves tend to remain at rest. This is because the inertia of the leaves tend to resist the to and fro motion. Due to this reason, the leaves fall down from the tree when shaken vigorously.
The velocity of the ball changes four times. As a football player kicks the football, its speed changes from zero to a certain value. As a result, the velocity of the ball gets changed. In this case, the player applied a force to change the velocity of the ball. Another player kicks the ball towardsRead more
The velocity of the ball changes four times.
As a football player kicks the football, its speed changes from zero to a certain value. As a result, the velocity of the ball gets changed. In this case, the player applied a force to change the velocity of the ball. Another player kicks the ball towards the goal post. As a result, the direction of the ball gets changed. Therefore, its velocity also changes.
In this case, the player applied a force to change the velocity of the ball. The goalkeeper collects the ball. In other words, the ball comes to rest. Thus, its speed reduces to zero from a certain value. The velocity of the ball has changed. In this case, the goalkeeper applied an opposite force to stop/change the velocity of the ball. The goalkeeper kicks the ball towards his team players. Hence, the speed of the ball increases from zero to a certain value. Hence, its velocity changes once again. In this case, the goalkeeper applied a force to change the velocity of the ball.
Inertia is the measure of the mass of the body. The greater is the mass of the body; the greater is its inertia and vice-versa. (a) Mass of a stone is more than the mass of a rubber ball for the same size. Hence, inertia of the stone is greater than that of a rubber ball. (b) Mass of a train is moreRead more
Inertia is the measure of the mass of the body. The greater is the mass of the body; the greater is its inertia and vice-versa.
(a) Mass of a stone is more than the mass of a rubber ball for the same size. Hence, inertia of the stone is greater than that of a rubber ball.
(b) Mass of a train is more than the mass of a bicycle. Hence, inertia of the train is greater than that of the bicycle.
(c) Mass of a five rupee coin is more than that of a one-rupee coin. Hence, inertia of the five rupee coin is greater than that of the one-rupee coin.
Here, r = 42250 km = 42250000 m T = 24 h = 24 × 60 × 60 s Using Speed, v = 2πr ÷ T v = (2 × 3.14 × 42250000) ÷ (24 × 60 × 60) m/s = 3070.9 m/s = 3.07 km/s For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
Here,
r = 42250 km = 42250000 m
T = 24 h = 24 × 60 × 60 s
Using Speed, v = 2πr ÷ T
v = (2 × 3.14 × 42250000) ÷ (24 × 60 × 60) m/s
= 3070.9 m/s = 3.07 km/s
(a) Yes, a body can have acceleration even when its velocity is zero. When a body is thrown up, at highest point its velocity is zero but it has acceleration equal to acceleration due to gravity. (b) Yes, an acceleration moving horizontally is acted upon by acceleration due to gravity that acts vertRead more
(a) Yes, a body can have acceleration even when its velocity is zero. When a body is thrown up, at highest point its velocity is zero but it has acceleration equal to acceleration due to gravity.
(b) Yes, an acceleration moving horizontally is acted upon by acceleration due to gravity that acts vertically downwards.
Here, u = 0 m/s, s = 20 m, a = 10 ms⁻², v = ?, t = ? Using v² – u² = 2as We have, v² – 0² = 2 × 10 × 20 = 400 ⇒ v = 20 ms⁻¹. and t = (v – u) ÷ a = 20 ÷ 10 = 2 s. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
Here, u = 0 m/s, s = 20 m, a = 10 ms⁻², v = ?, t = ?
Using v² – u² = 2as
We have, v² – 0² = 2 × 10 × 20 = 400 ⇒ v = 20 ms⁻¹.
and t = (v – u) ÷ a = 20 ÷ 10 = 2 s.
Here, u = 0 m/s a = 3 ms⁻² t = 8 s Using, s = ut + ½ at² s = 0 × 8 + ½ × 3 × 8² = 96 m. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
Here, u = 0 m/s
a = 3 ms⁻²
t = 8 s
Using, s = ut + ½ at²
s = 0 × 8 + ½ × 3 × 8² = 96 m.
Explain, why is it difficult for a fireman to hold a hose, which ejects large amounts of water at a high velocity.
Due to the backward reaction of the water being ejected When a fireman holds a hose, which is ejecting large amounts of water at a high velocity, then a reaction force is exerted on him by the ejecting water in the backward direction. This is because of Newton's third law of motion. As a result of tRead more
Due to the backward reaction of the water being ejected
When a fireman holds a hose, which is ejecting large amounts of water at a high velocity, then a reaction force is exerted on him by the ejecting water in the backward direction. This is because of Newton’s third law of motion. As a result of the backward force, the stability of the fireman decreases.
Hence, it is difficult for him to remain stable while holding the hose.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-9/
If action is always equal to the reaction, explain how a horse can pull a cart.
A horse pushes the ground in the backward direction. According to Newton's third law of motion, a reaction force is exerted by the Earth on the horse in the forward direction. As a result, the cart moves forward. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-Read more
A horse pushes the ground in the backward direction. According to Newton’s third law of motion, a reaction force is exerted by the Earth on the horse in the forward direction. As a result, the cart moves forward.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-9/
Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?
Due to the inertia of the passenger Everybody tries to maintain its state of motion or state of rest. If a body is at rest, then it tries to remain at rest. If a body is moving, then it tries to remain in motion. In a moving bus, a passenger moves with the bus. As the driver applies brakes, the busRead more
Due to the inertia of the passenger
Everybody tries to maintain its state of motion or state of rest. If a body is at rest, then it tries to remain at rest. If a body is moving, then it tries to remain in motion. In a moving bus, a passenger moves with the bus. As the driver applies brakes, the bus comes to rest. But, the passenger tries to maintain his state of motion. As a result, a forward force is exerted on him.
Similarly, the passenger tends to fall backwards when the bus accelerates from rest. This is because when the bus accelerates, the inertia of the passenger tends to oppose the forward motion of the bus. Hence, the passenger tends to fall backwards when the bus accelerates forward.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
Explain why some of the leaves may get detached from a tree if we vigorously shake its branch.
Some leaves of a tree get detached when we shake its branches vigorously. This is because when the branches of a tree are shaken, it moves to and fro, but its leaves tend to remain at rest. This is because the inertia of the leaves tend to resist the to and fro motion. Due to this reason, the leavesRead more
Some leaves of a tree get detached when we shake its branches vigorously. This is because when the branches of a tree are shaken, it moves to and fro, but its leaves tend to remain at rest. This is because the inertia of the leaves tend to resist the to and fro motion. Due to this reason, the leaves fall down from the tree when shaken vigorously.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
In the following example, try to identify the number of times the velocity of the ball changes: “A football player kicks a football to another player of his team who kicks the football towards the goal. The goalkeeper of the opposite team collects the football and kicks it towards a player of his own team”. Also identify the agent supplying the force in each case.
The velocity of the ball changes four times. As a football player kicks the football, its speed changes from zero to a certain value. As a result, the velocity of the ball gets changed. In this case, the player applied a force to change the velocity of the ball. Another player kicks the ball towardsRead more
The velocity of the ball changes four times.
As a football player kicks the football, its speed changes from zero to a certain value. As a result, the velocity of the ball gets changed. In this case, the player applied a force to change the velocity of the ball. Another player kicks the ball towards the goal post. As a result, the direction of the ball gets changed. Therefore, its velocity also changes.
In this case, the player applied a force to change the velocity of the ball. The goalkeeper collects the ball. In other words, the ball comes to rest. Thus, its speed reduces to zero from a certain value. The velocity of the ball has changed. In this case, the goalkeeper applied an opposite force to stop/change the velocity of the ball. The goalkeeper kicks the ball towards his team players. Hence, the speed of the ball increases from zero to a certain value. Hence, its velocity changes once again. In this case, the goalkeeper applied a force to change the velocity of the ball.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
Which of the following has more inertia?
Inertia is the measure of the mass of the body. The greater is the mass of the body; the greater is its inertia and vice-versa. (a) Mass of a stone is more than the mass of a rubber ball for the same size. Hence, inertia of the stone is greater than that of a rubber ball. (b) Mass of a train is moreRead more
Inertia is the measure of the mass of the body. The greater is the mass of the body; the greater is its inertia and vice-versa.
(a) Mass of a stone is more than the mass of a rubber ball for the same size. Hence, inertia of the stone is greater than that of a rubber ball.
(b) Mass of a train is more than the mass of a bicycle. Hence, inertia of the train is greater than that of the bicycle.
(c) Mass of a five rupee coin is more than that of a one-rupee coin. Hence, inertia of the five rupee coin is greater than that of the one-rupee coin.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
An artificial satellite is moving in a circular orbit of radius 42250 km. Calculate its speed if it takes 24 hours to revolve around the earth.
Here, r = 42250 km = 42250000 m T = 24 h = 24 × 60 × 60 s Using Speed, v = 2πr ÷ T v = (2 × 3.14 × 42250000) ÷ (24 × 60 × 60) m/s = 3070.9 m/s = 3.07 km/s For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
Here,
r = 42250 km = 42250000 m
T = 24 h = 24 × 60 × 60 s
Using Speed, v = 2πr ÷ T
v = (2 × 3.14 × 42250000) ÷ (24 × 60 × 60) m/s
= 3070.9 m/s = 3.07 km/s
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
State which of the following situations are possible and give an example for each of these:
(a) Yes, a body can have acceleration even when its velocity is zero. When a body is thrown up, at highest point its velocity is zero but it has acceleration equal to acceleration due to gravity. (b) Yes, an acceleration moving horizontally is acted upon by acceleration due to gravity that acts vertRead more
(a) Yes, a body can have acceleration even when its velocity is zero. When a body is thrown up, at highest point its velocity is zero but it has acceleration equal to acceleration due to gravity.
(b) Yes, an acceleration moving horizontally is acted upon by acceleration due to gravity that acts vertically downwards.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
A ball is gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of 10 m s-2, with what velocity will it strike the ground? After what time will it strike the ground?
Here, u = 0 m/s, s = 20 m, a = 10 ms⁻², v = ?, t = ? Using v² – u² = 2as We have, v² – 0² = 2 × 10 × 20 = 400 ⇒ v = 20 ms⁻¹. and t = (v – u) ÷ a = 20 ÷ 10 = 2 s. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
Here, u = 0 m/s, s = 20 m, a = 10 ms⁻², v = ?, t = ?
Using v² – u² = 2as
We have, v² – 0² = 2 × 10 × 20 = 400 ⇒ v = 20 ms⁻¹.
and t = (v – u) ÷ a = 20 ÷ 10 = 2 s.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
A motorboat starting from rest on a lake accelerates in a straight line at a constant rate of 3.0 m s–2 for 8.0 s. How far does the boat travel during this time?
Here, u = 0 m/s a = 3 ms⁻² t = 8 s Using, s = ut + ½ at² s = 0 × 8 + ½ × 3 × 8² = 96 m. For more answers visit to website: https://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/
Here, u = 0 m/s
a = 3 ms⁻²
t = 8 s
Using, s = ut + ½ at²
s = 0 × 8 + ½ × 3 × 8² = 96 m.
For more answers visit to website:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-9/science/chapter-8/