Energy and Force Gravity Work Required to Move at Constant Speed Questions Discussion

Need help with my Physics question – I’m studying for my class.

1. A 550 kg crate rests on the floor:

a) How much work is required to move it at constant speed 2 meters along the floor against a frictional force of 150 N ?

b) How much work is required to lift it vertically at constant speed 2 meters against the force of gravity?

2. Calculate the kinetic energy of a 55 kg person running at a speed of 9.0 m/s.

3. A 65 kg hiker starts at an elevation of 1500 m and climbs to the top of a 2600 m peak.

a) What is the hiker’s change in potential energy?

b) What is the minimum work required of the hiker?

c) Considering that the only force operating on the hiker is gravity, can the actual work be more than this minimum work (for example suppose the hiker does not climb straight up) ? Explain.

d) In the real world there are forces other than gravity which act on the hiker, such as friction, air resistance, etc.. Considering the real world, can the actual work done be more than the minimum work, even if the hiker climbs straight up? Explain.