Question

A force of 1.00x10² N is applied to a box with a mass of 2.00x10¹ kg, moving it across a floor. If the friction between the box and the floor is 2.00x10¹ N, what is the acceleration of the box?

Answer 1

Let's apply the Newton's Second Law of Motion:

$$\sum F_x=ma_x,$$ $$F_{appl}-F_{fr}=ma,$$ $$a=\dfrac{F_{appl}-F_{fr}}{m},$$ $$a=\dfrac{1.0\cdot10^2\ N-2.0\cdot10^1\ N}{2.0\cdot10^1\ kg}=4.0\ \dfrac{m}{s^2}.$$

Answer:

$a=4.0\ \dfrac{m}{s^2}.$