The coefficient of kinetic friction was choosen because the box is sliding across the surface. If the box was at rest then the coefficient of statics friction whould have been used.
This is waht your paper would look like. You do not have to write the force questions.
Questions to ask to help you decide what forces are acting onthe body?
- Is it on a planet? Yes, therefore is experiences weight.
- Is there a contact surface? Yes. therefore there is anormal force.
- Is there friction? Yes, therefore it experiences friction.
- Is there drag? No.
- Is there a rope? No.
- Other forces? No.