Two persons manage to push a motorcar of mass`1200kg` at a uniform velocity along a level road. The same motorcar can be pushed by three persons to produce an acceleration of `0.2m//s^(2)`. With what force does each person push the motorcar? (Assume that all persons push the motorcar with the same muscular effort).

Explanation

Here mass of motorcar m=1200kg
Let each person exerts a push F on the motorcar
Total push of two person =F+F=2F
As this push gives a uniform velocity to the motorcar along a level road, it must be a measure of the force of friction (F) between the motorcar and the road
i.e., F=2F
When three person push, total force applied
`=F+F+F=3F`
Force that produces acceleration i.e., `=ma=3F-F=3F-2F=F`
or `F=ma=1200 times 0.2=240 N`