Question

How much work must be done on a 6000-kg stone car to increase its speed
from 5 m/s to 10 m/s?

Answer 1

225000J

Explanation:

`W=F * S.............1`

where

W= work done

F=force

S=distance

but F=ma

so we can write the equation

`F=m ((v - u))/(t) .........2`

Also,

`S = ( (u + v)/(2))t...........3`

We put equation (2) and equation (3) into equation (1)

This implies,

`W =m((v - u))/(t) * ( (u + v)/(2))t`

`W =m(v - u)* ( (u + v)/(2))`

From the question

m=6000kg

u=5m/s

v=10m/s

By substitution we obtain

`W =6000(10 - 5)* ( (5 + 10)/(2))`

`W =3000 * 5*15`

`W=225000J`