Question

Suppose you have a 120-kg wooden crate resting on a wood floor. (a) What maximum force can you exert horizontally on the crate without moving it? (b) If you continue to exert this force once the crate starts to slip, what will the magnitude of its acceleration then be? What is the maximum force to exert horizontally on a 120-kg wooden crate without moving it?

a) 1,170 N
b) 1,400 N
c) 1,560 N
d) 1,800 N

Answer 1

To determine the maximum force that can be exerted horizontally on the wooden crate without moving it, we need to consider the maximum force of static friction. Once the crate starts to slip, the maximum force is determined by the force of kinetic friction.

Step-by-step explanation:

To determine the maximum force that can be exerted horizontally on the wooden crate without moving it, we need to consider the maximum force of static friction. The maximum force of static friction can be found using the equation:

Maximum force of static friction = coefficient of static friction × normal force
given that the crate has a mass of 120 kg and is resting on a wood floor, the normal force can be calculated as:

Normal force = mass × acceleration due to gravity

Once the crate starts to slip, the maximum force is determined by the force of kinetic friction. The force of kinetic friction can be found using the equation:

Force of kinetic friction = coefficient of kinetic friction × normal force

Since the coefficient of kinetic friction is known, the magnitude of the crate's acceleration can be determined using Newton's second law:

F = m × a

where F is the net force and m is the mass of the crate.