IX GRAVITATION QUESTIONS

1.       Calculate the gravitational force between two iron balls each of mass 1 kg separated by a distance of 1 m. Given, G = 6·673 x 10-¹¹ Nm² kg-².

2.       Find the distance between two stones each of mass 2 kg so that the gravitational force between them is 1 N.

3.       The gravitational force between two objects is 2 N. What will be the gravitational force between these objects if the distance between them becomes double?

4.       The gravitational force of two iron balls is 4 N. What will be the gravitational force between them if the distance between them is reduced to half?

5.       A body of mass 1 kg is placed at a distance of 2 m from another body of mass 10 kg. At what distance from the body of mass 1 kg, another body of mass 5 kg must be placed so that the net gravitational force acting on the body of mass 1 kg is zero?

6.    A stone is dropped from the edge of a roof. Find the speed of the stone at 2 s after the stone was dropped.

7.     A stone is dropped from the edge of a roof. Find the distance traveled by the stone in 2 s after its release.

8.     A ball is thrown upward with a speed of 10 ms-¹. Calculate, the speed of the ball after 1 second.

9.       A ball is thrown upward with a speed of 15 ms-^I. Find the distance traveled by the ball in 2 s.

10.   A boy drops a coin from the top of a tower 50 m high. Find the time taken by the coin to reach the ground.

11.   A stone dropped from the bridge hits the water after 2 s. Find the height of the bridge.

12.   A stone is dropped from a height of 10 m. Find the speed with which the stone hits the ground.

13.   A stone is thrown vertically upward with a speed of 29·4 ms-^I. Find

(i) the time taken by the stone to reach the maximum height.

(ii) maximum height reached by the body and

(iii) show that time of ascent is equal to time of descent.