Question

A 5-kg box is at rest on the floor. The coefficient of static friction between the box and the floor is 0.4. A horizontal force of 50 N is applied to the box. What is the maximum force of static friction that can act on the box?

1) 20 N
2) 40 N
3) 50 N
4) 80 N

Answer 1

The maximum force of static friction for a 5-kg box with a 0.4 coefficient of static friction on the floor is 19.6 N; hence, with a 50 N horizontal force applied, the box will move.

Step-by-step explanation:

The question involves calculating the maximum force of static friction that can act on a 5-kg box with a coefficient of static friction of 0.4 on the floor. To find this, we use the formula for maximum static friction, which is fs(max) = μs N.

In this case, N is the normal force, and it is equal to the weight of the box, which is mg = (5 kg)(9.80 m/s²) = 49 N. Applying the coefficient of static friction of 0.4, the maximum static friction force would be (0.4)(49 N) = 19.6 N. Since the applied force of 50 N is greater than the maximum static friction, the box will move.