Question

The velocity time graph of a ball of mass 50g moving along a straight line on a long table is given.


How much force does the table exert on the ball to bring it to rest.​

Answer 1

Answer:

Mass of the body, m=20 g=0.02 kg

From the given graph, we note that

Initial velocity, u=20 m/s=20 m/s

Final velocity, v=0 m/s

Time taken, t=10−0=10s

The force exerted on the ball is,

F=m x a

F=m x (v−u)/t

F=−0.04 N

The negative sign shows that the friction force exerted by the table is opposite to the direction of motion of the ball.

Answer 2

Given:

Mass of the body, m=50g

m=0.05kg

In the given graph

Initial velocity, u=20cm/s = 0.2m/s

Final velocity, v=0

Time t=10-0=10 s

The force exerted on the ball

F=m × a

F=m × (v-u)/t

 =0.05 ×(0-0.2)/10

 =0.05 ×-0.2/10

 =-0.001N

The friction force exerted by the table is opposite to the direction of motion of the ball because of negative sign.

Hence the answer is 0.001N