A ball is thrown vertically upwards, reaches its highest point, then drops down to the ground, bounces once,reaches a height of 1.2 m, then falls again and finally rests on the grass. At which one or more times is the gravitational force on the ball zero?

Question

BlackTom AI · Accepted Answer

Consider the scenario: a ball moving under the influence of gravity on Earth. Gravity is a constant downward force acting on the ball at all times during its motion, unless an external condition (like being in a gravity-free environment) were introduced.

Option a: At the highest point it reached. Even at the top, the ball has weight due to gravity; there is no moment where gravity vanishes.

Option b: At the instant the ball hit the ground for the first time. Right before and after impact, the ball still experiences weight; the contact force with the ground may dominate the net force temporarily, but gravity itself is still acting downward.

Option c: Whenever the ball was moving up. While moving upward, gravity acts downward, causing deceleration, but the gravitational force is not zero.

Option d: When the ball had bounced up to a height of 1.2 m. At that peak of the bounce, gravity is still pulling downward; the force is not zero.

Option e: Before the ball was thrown. Even before release, the ball experiences weight if it is resting on a surface; the force of gravity acts downward regardless of motion.

Option f: Whenever it was moving down. Like when moving up, gravity acts downward during the descent; the force does not disappear.

Option g: When the ball rested on the grass. While at rest, gravity still acts downward; the normal force from the ground may balance it, but gravity itself remains.

Option h: The ball always experiences the force of gravity. This is correct because gravity is present at all times on Earth, independent of motion state.

Option i: At the exact instant the ball was thrown up. The moment of throw does not remove gravity; the ball still has weight during and after the throw.

In summary, every moment the ball is in Earth’s gravitational field, gravity acts downward on it; there is no instant when the gravitational force is zero. The only statement that accurately reflects this universal presence is option h.

A ball is thrown vertically upwards, reaches its highest point, then drops down to the ground, bounces once,reaches a height of 1.2 m, then falls again and finally rests on the grass. At which one or more times is the gravitational force on the ball zero?

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A ball is thrown vertically upwards, reaches its highest point, then drops down to the ground, bounces once,reaches a height of 1.2 m, then falls again and finally rests on the grass. At which one or more times is the gravitational force on the ball zero?

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