Question

3. A worker pushes a box across the floor to the right at a constant speed with a force of 25N. What

Answer 1

Answer:

Friction between the box and the floor is 25N to the left.

Explanation:

According to Newton's second law of motion, the net force acting on an object is equal to the produce between the object's mass and its acceleration:

$F_{net}=ma$

where

m is the mass of the object

a is its acceleration

In this problem, we have two forces acting on the object:

- The applied force, F = 25 N, to the right

- The force of friction $F_f$, opposing the motion of the box, so to the left

So we can write the net force as

$F_{net}=F-F_f$

Also, we know that the box is moving at constant speed: this means its acceleration is zero, so

$a=0$

Therefore

$F_{net}=0$

WHich means:

$F-F_f=0$

And therefore,

$F_f=F=25 N$

which means that the force of friction is also 25 N.