How long did Skylab orbit the earth?

What’s #16 asking me and how do i solve it?

Give one example to show that when substances are mixed, it may result in a chemical or a physical change depending on the conditions.

In a system with only a single force acting upon a body, what is the relationship between the change in kinetic energy and the work done by the force? answers: work is equal to the change in kinetic energy. work depends on the square of the change in potential energy. work is equal to the negative of the change in kinetic energy. work is equal to the square of the change in kinetic energy