1. Simple Machines Power

2. Power: Is the rate at which work is done A machine that does a certain amount of work the fastest develops the most power Unit:  Watt (W) or J/s

3. What is the power of a bulldozer that does 5.5 x 10 4 J of work in 1.1s?

4. How much power is developed by a 60kg boy running up a 4.5m high flight of stairs in 4s?

5. A boy who can generate 500W runs up a flight of stairs in 5s. How high are the stairs if the boy has a mass of 62kg?

6. The motor for an elevator can produce 2200W of power. The elevator has a mass of 1100kg. Ignoring air resistance & friction, at what constant speed will the elevator rise? v

7. A 1500kg car accelerates uniformly from rest to a speed of 27.78m/s in 10s. What power is required to produce this motion? (ignore friction)

9. A gondola travels at a rate of 2m/s with a total mass of 1200kg when full. 25 o C 3500m How much power does the motor produce to move the gondola 3500m along a hill at a 25 o C angle?

10. Find d R : Find F R : Find t: Find P:

11. To move a 2000N air conditioning unit to the roof of a building 10m high, a winch is used. It is set up to move the air conditioner along a frictionless ramp with a mechanical advantage of 4. To reduce the stress on the cable, the winch is set to move the air conditioner at 2m/s. 2000N 10m v=2m/s What is the power of the winch?

12. d R = 10m F R = 2000N Find t: