Question

17. If a ball has a mass of 0.7 kg and changes its velocity from 2 m/s to 10 m/s, how much work was done on it?

a. 36.43
b. 33.6J
C. 8]
d. cannot be determined

Answer 1

33.6 J is the work done on the ball.

Option: b

Step-by-step explanation:

given that,

Mass of the ball (m) is 0.7 kg.

"Initial velocity" of the ball
`({V_i}^2)` is 2 m/s.

"Final velocity" of the ball
`({V_f}^2)` is 10 m/s.

We need to find how much work is done on the ball.

We know that the "work done" on the ball which is moving with a velocity is equal to the change in "kinetic energy" of the object therefore,

`Work done =(1)/(2)m*{V_f}^2-(1)/(2)m*{V_i}^2`

`Work done =(1)/(2)m({V_f}^2-{V_i}^2)`

Substitute the given values in the the above formula,

`Work done =(1)/(2)0.7({10}^2-{2}^2)`

`Work done =(1)/(2)0.7(100-4)`

`Work done =(1)/(2)0.7(96)`

`Work done =(1)/(2)(67.2)`

Work done = 33.6 J