Question

A ball is dropped from a space craft revolving around the earth at a height of $120km$. What will happen to the ball ?

• A. it will continue to move with the same velocity long the original orbit of space craft
• B. it will move with the same speed, tangentially to the space craft
• C. it will fall down to the earth gradually
• D. it will go very far in the space

Answer 1

Answer: (A)

it will continue to move with the same velocity long the original orbit of space craft

As the ball is initially at rest w.r.t the space craft which is revolving around earth with a velocity $v$. Thus due to inertia of motion, the ball will also revolve around earth with velocity $v$ in the same orbit of space craft such that net force acting on the ball is zero.