Question

A truck of mass 200 kg is moved under a force of 1000 N on a smooth surface. On a rough surface, the truck experiences a frictional force of 200 N offered by the road. Find the percentage change in the acceleration.

• A. -20%
• B. -10%
• C. 25%
• D. 50%

Answer 1

The correct option is A -20%

The acceleration of the truck on the smooth surface is as follows:
$a_1$ = $\frac{F}{m}$ ⇒ $\frac{1000}{200}$ = 5 $m{s}^{-2}$
The net force acting on the truck on the rough surface is,
$F_{net}$ = 1000 - 200 = 800 N
The acceleration of the truck on the rough surface is as follows:
$a_2$ = $\frac{F_{net}}{m}$ ⇒ $\frac{800}{200}$ = 4 $m{s}^{-2}$
Thus, the percentage change is as follows:
% change = $\frac{a_2-a_1}{a_1}$ x 100% ⇒$\frac{4-5}{5}$ x 100% = -20%
The negative sign indicates that there is a reduction in acceleration.