A dockworker loading crates on a ship finds that a 20 kg crate, initially at rest on a horizontal surface, requires a 73 N horizontal force to set it in motion. However, after the crate is in motion, a horizontal force of 50 N is required to keep it moving with a constant speed. Find the coefficients of static and kinetic friction between crate and floor. *PLEASE HELP*

I try to looking for this answer but now I think I am a person should answer this question ^^. Ok

Sum F = ma ( because it get loading the crates )
Fp - F(fr) = ma
Fp = ma + F(fr)
Fp = ma + u(k) mg
=> u(k) = (Fp - ma) / mg ( with ma is 0 )
so u(k) = 59/ ( 22*9.8) ( because kenetic friction always moving )

The u(s) you guys can do the same thing , just replace another force number to the equation.

participation

To find the coefficients of static and kinetic friction between the crate and the floor, we can use the following equations:

Coefficient of static friction (μs):
μs = F_s / N

Coefficient of kinetic friction (μk):
μk = F_k / N

Where:
- F_s is the static friction force
- F_k is the kinetic friction force
- N is the normal force (equal to the weight of the crate)

Let's go step by step to find the coefficients:

Step 1: Find the weight (normal force) of the crate
The weight of an object is given by the formula:
Weight = mass * gravity

Given that the mass of the crate is 20 kg and gravity is approximately 9.8 m/s^2, we can calculate the weight:
Weight = 20 kg * 9.8 m/s^2 = 196 N

Step 2: Calculate the coefficient of static friction (μs)
The coefficient of static friction can be found using the static friction force, which is the force required to set the crate in motion. This force is given as 73 N.

μs = F_s / N = 73 N / 196 N ≈ 0.372

So, the coefficient of static friction (μs) between the crate and the floor is approximately 0.372.

Step 3: Calculate the coefficient of kinetic friction (μk)
The coefficient of kinetic friction can be found using the kinetic friction force, which is the force required to keep the crate moving at a constant speed. This force is given as 50 N.

μk = F_k / N = 50 N / 196 N ≈ 0.255

Therefore, the coefficient of kinetic friction (μk) between the crate and the floor is approximately 0.255.

In summary:
The coefficient of static friction (μs) between the crate and the floor is approximately 0.372, while the coefficient of kinetic friction (μk) is approximately 0.255.

The crate's weight is M g = 196 N

That is the "normal force" on the surface below.

Mu-static = 73/196 = ___

Mu_kinetic = 50/196 = ___

Review the definitions of static and kinetic friction coefficients.

This is pretty basic stuff