Answer:

Explanation:
First, we write the equations of motion for each axis. Since the crate is sliding with constant speed, its acceleration is zero. Then, we have:

Where T is the tension in the rope, F is the force exerted by the first worker, f_k is the frictional force, N is the normal force and mg is the weight of the crate.
Since
and
, we can rewrite the first equation as:

Now, we solve for
and calculate it:

This means that the crate's coefficient of kinetic friction on the floor is 0.18.
ANSWER:
300 J
STEP-BY-STEP EXPLANATION:
To know the work required, we must calculate the work in both cases, the difference would be the amount of work necessary for the speed to increase. The work done is the same as the amount of energy increase. The formula for kinetic energy is:

We calculate in each case:

We calculate the difference between the two to find out the work required:

The work required is 300 J
Answer:
As global population a.) <u>increases</u> food production must a.) <u>increase</u>.
Example:
More people means more food must be produced.