Question

The velocity-distance graph of small wooden ball of

mass 40 g moving along a straight line on a long table is shown here. The initial velocity of ball is

20 cm s and the ball finally comes to rest after

covering a distance of 200 cm

(a) What is the acceleration of the bail during its

20

15T

10

motion ?

(b) What force is acting on the ball due to the table ?

(c) What is the nature of the force acting on the

ball moving on the table ?

(d) What is the direction of the force ?

5

50 100 150 200

C​

Answer 1

Answer:

Given Initial velocity of ball, u=49 m/s

Let the maximum height reached and time taken to reach that height be H and t respectively.

Assumption: g=9.8 m/s

2

holds true (maximum height reached is small compared to the radius of earth)

Velocity of the ball at maximum height is zero, v=0

v

2

−u

2

=2aH

0−(49)

2

=2×(−9.8)×H

⟹H=122.5 m

v=u+at

0=49−9.8t

⟹t=5 s

∴ Total time taken by ball to return to the surface, T=2t=10 s