Question

How much horizontal force must a girl apply to a 50.0 kg dresser to accelerate it at $0.40m/s^2$ along a horizontal surface if the force of friction is 70.0 N?

• A. 20.0 N
• B. 70.0 N
• C. 50.0 N
• D. 80.0 N
• E. 90.0 N

Answer 1

The correct option is E 90.0 N

Given : $m=50kg$ $a=0.40$ $m/s^2$ $f=70$ N

Let the horizontal force to be applied be $F$.

$\therefore$ $ma=F-f$

OR $50\times 0.4=F-70$ $⟹F=90.0$ N