Question

A truck starts from rest and rolls down a hill with a constant acceleration. It travels a distance of $400m$ in $20s$. Find the force acting on it if its mass is $7\text{metric tonnes}$.

• A. $14000N$
• B. $7000N$
• C. $3500N$
• D. $21000N$

Answer 1

The correct option is A $14000N$

1 metric tonne $=1000kg$
Initial velocity of truck, $u=0;time,t=0s;$
distance covered, $s=400m;acceleration,a=?$;
mass of truck, $m=7$ metric tonnes $=7000kg$; force on truck, $F=?$

We know, $s=ut+\frac{1}{2}a{t}^2$
$\Rightarrow 400=0\times 20+\frac{1}{2}\times a\times (20{)}^2$
$\Rightarrow 400-200a$ or $a=\frac{400}{200}=2m{s}^{-2}$
Force on truck, $F=ma=7000\times 2=14000N$