Question

the velocity timegraph of ball of mass 20g is moving along a straight line.how much force doe the table exert on the ball to bring it to rest?

Answer 1

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

From the given graph, we note that

Initial velocity, u = 20 cm/s = 0.20 m/s

Final velocity, v = 0 cm/s

Time taken, t = 10 - 0 = 10s

The force exerted on the ball is,

F= 0.0004N

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

Answer 2

Answer:

-0.0004 N

Explanation

The Initial velocity of the ball=20 cm/s

Due to friction by table velocity of the ball decreases

Thus,u=20cm/s,v=0cm/s and t=10s

a=v-u/t

=0-20/10

=-2 cm/s^2

-2 cm/s^2= -0.02 m/s^2

The force exerted on the ball

F=ma

=20/1000 kg

=-0.02 m/s^2

=-0.0004 N

•The negative sign in Force indicates the table is opposite to the direction of motion of the ball