Question

A body of mass $45\, kg$. is moving with a constant velocity of $10 \,m / s$. A constant force acts on the body for four second, and the speed of the body becomes $2 \,m / s$ in opposite direction, calculate the magnitude of acceleration produced in $m / \sec ^{2}$.

Answer 1

$m =45 \,kg$
$F = ma$
$\therefore a=\frac{F}{m}$
from $v=4+a t$
$-2=10+a \times 4$
$4 a =-12 \therefore a =-3 \,m / s ^{2}$
$\therefore F=m a=45 \times-3=-135\, N$