1. If a body is thrown from the Earth with a velocity of 11.2 km per second, then the body will never return to the Earth; Option [A]. This velocity exceeds the escape velocity of Earth, ensuring that the body will continue moving away from Earth indefinitely, unable to return due to the gravitationalRead more

    If a body is thrown from the Earth with a velocity of 11.2 km per second, then the body will never return to the Earth; Option [A]. This velocity exceeds the escape velocity of Earth, ensuring that the body will continue moving away from Earth indefinitely, unable to return due to the gravitational pull. The escape velocity of Earth, approximately 11.2 km/s at the Earth’s surface, represents the minimum speed required for an object to break free from Earth’s gravitational field and enter space. Once a body achieves or exceeds this velocity, it is no longer bound by Earth’s gravity and will not return. Therefore, option A, “Never return to the Earth,” is the correct answer. This principle is fundamental to understanding space travel and celestial mechanics, as it governs the conditions under which objects can escape from planetary bodies and explore the cosmos. In summary, a body thrown from Earth with a velocity of 11.2 km/s will not return, as it has achieved escape velocity and will continue its journey away from Earth indefinitely.

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  2. When a stone is brought from the surface of the moon to the Earth, its mass remains constant; option [B]. Mass is an intrinsic property of an object, representing the amount of matter it contains, and it does not change regardless of the gravitational environment. However, its weight will change dueRead more

    When a stone is brought from the surface of the moon to the Earth, its mass remains constant; option [B]. Mass is an intrinsic property of an object, representing the amount of matter it contains, and it does not change regardless of the gravitational environment. However, its weight will change due to the difference in gravitational acceleration between the moon and the Earth. Weight is the force exerted by gravity on an object and is calculated by multiplying mass by the gravitational acceleration. Since the gravitational acceleration on the Earth is stronger than that on the moon, the stone’s weight will increase when brought to Earth. This change in weight occurs because weight is dependent on both mass and the strength of the gravitational field. Therefore, the correct answer is option [B]. Its weight will change, but not the mass. This distinction between mass and weight is fundamental in physics and is essential for understanding how objects behave in different gravitational environments.

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  3. A person sitting in a lift feels that their weight is more when the lift is going up at an accelerated speed, which is; option [B]. This sensation occurs due to the interplay between gravitational force and the lift's acceleration. When the lift accelerates upward, the floor exerts an additional forRead more

    A person sitting in a lift feels that their weight is more when the lift is going up at an accelerated speed, which is; option [B]. This sensation occurs due to the interplay between gravitational force and the lift’s acceleration.

    When the lift accelerates upward, the floor exerts an additional force on the person, adding to the gravitational force already acting on them. This combined force, known as apparent weight, is greater than the person’s actual weight. As a result, the person feels heavier than they would at rest or when the lift is moving at a constant velocity.

    Conversely, when the lift is coming down at an accelerated speed (option A), the floor exerts less force on the person, reducing their apparent weight. Similarly, when the lift is moving at a constant velocity in either direction (options C and D), the person experiences their actual weight without the additional effects of acceleration.
    Therefore, option [B] correctly identifies the scenario in which a person sitting in a lift feels that their weight is more: when the lift is going up at an accelerated speed.

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  4. The ball dropped from an artificial satellite revolving around the Earth will continue to revolve around the Earth in its orbit with the same period of time as the satellite; option [C]. This is because the ball shares the same gravitational influence and motion as the satellite. It follows the curvRead more

    The ball dropped from an artificial satellite revolving around the Earth will continue to revolve around the Earth in its orbit with the same period of time as the satellite; option [C]. This is because the ball shares the same gravitational influence and motion as the satellite. It follows the curvature of Earth’s surface, remaining in orbit without falling to Earth or being pulled towards the Moon. The gravitational force between the ball and the Earth keeps it in orbit, maintaining its trajectory around the planet. As long as the satellite remains in orbit, the ball dropped from it will also remain in orbit, moving along with the satellite at the same speed and direction. Therefore, option [C] accurately describes the behavior of the ball dropped from an artificial satellite, highlighting the continuous orbiting motion governed by gravitational forces and orbital mechanics, without being affected by other celestial bodies such as the Earth or the Moon.

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  5. The approximate height of a synchronous satellite from the Earth's surface is 36,000 km, which is; option [A]. Synchronous satellites, also known as geostationary satellites, orbit the Earth at the same rate as the Earth's rotation, appearing stationary relative to a fixed point on the Earth's surfaRead more

    The approximate height of a synchronous satellite from the Earth’s surface is 36,000 km, which is; option [A]. Synchronous satellites, also known as geostationary satellites, orbit the Earth at the same rate as the Earth’s rotation, appearing stationary relative to a fixed point on the Earth’s surface. This orbit is achieved when the satellite’s orbital period matches the Earth’s rotational period, which is approximately 24 hours. To maintain this synchronous orbit, the satellite must be located at a specific distance from the Earth’s surface. This distance, known as the geostationary orbit altitude, is approximately 36,000 km above the Earth’s equator. At this altitude, the satellite completes one orbit around the Earth in 24 hours, matching the Earth’s rotational period and enabling it to remain stationary relative to a fixed point on the Earth’s surface. Therefore, option A correctly identifies the approximate height of a synchronous satellite from the Earth’s surface, highlighting its significance in telecommunications, weather monitoring, and other applications requiring continuous coverage of a specific area on the Earth’s surface.

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