Question

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.)

• A. $240N$
• B. $480N$
• C. $1020N$
• D. $120N$

Answer 1

The correct option is A $240N$

Mass of the car$=$1200 kg
According to question only two people are able to move the car, so the Acceleration acquired by car is given by third the person.
Acceleration produced by car when pushed by third person $=$0.2 m$s^{-2}$
we know F$=$ma
Force applied by third person $\left(F\right)=ma$
or $=1200\times 0.2$
or $=240kgm{s}^{-2}$(N)
according to question all persons pushing the motorcar with the same muscular effort,so the each person applies a force of $240N$.