Question

A 1.0 kg box on a horizontal surface experiences a 3.0 N horizontal frictional force. How much force must be applied horizontally to the box to cause it to accelerate at 1.0 $m/s^2$?

• A. 1.0 N
• B. 2.0 N
• C. 3.0 N
• D. 4.0 N
• E. 5.0 N

Answer 1

The correct option is D 4.0 N

Given : $f=3.0$ N $a=1.0$ $m/s^2$ $m=1.0kg$

Let the horizontal required be $F$.

From figure, $ma=F-f$

$\therefore$ $1\times 1=F-3$ $⟹F=4.0$ N