Ball falls to earth, and earth moves to ball?!! Sandeepan Dhar
Choudhary asked: “When the ball falls on the earth, the earth
also moves up to meet it. But the motion of the earth is not
noticeable. Explain why?” The force exerted by the ball on earth
is same as the force exerted by the earth on the ball. The
acceleration of the ball towards earth is approximately 10 m/s2.
The acceleration of earth towards the ball = force/mass of earth
≈ 10-23 m/s2 When the earth moves towards the ball with this
acceleration, the time required to travel the distance will be
very large. If we assume a distance of 1m, and from the equation
we get t ≈ 1012 seconds whereas the ball reaches the earth in
0.4 seconds [warning]In a nut shell, we can say that we cannot
notice the motion of earth towards the ball due to the extremely
low value of acceleration of earth towards the ball.[/warning]