1. Work and Power notes: In science, ‘work’ has a specific meaning
Work is ONLY done when a causes a change in the of an object in the of the applied force
i.e.
WORK EQUATION:
Work =
W = F x d

2. is measured in . 1 J = 1 N•m = 1 kg•m2/s2
1 joule is roughly equal to the
energy required to lift a small
apple 1 meter
*N measures force/weight
*m measures mass...
To find weight in N, need to use w=mg
James Prescott Joule

3. Practice!
A crane uses an average force of 5200 N to lift a crate 25 m. How much work does the crane do on the girder?

4. An apple weighing 1N falls a distance of 1m
An apple weighing 1N falls a distance of 1m. How much work is done on the apple by the force of gravity?

5. A mechanic uses a hydraulic life to raise a 1200 kg car 0
A mechanic uses a hydraulic life to raise a 1200 kg car 0.5 m off the ground. How much work does the lift do on the car?

6. POWER POWER is how much work is done in a given time
POWER: the rate at which or energy is converted.
power = work / time
Measured in
746 watts = 1 horsepower

7. Practice
While rowing across the lake during a race, John does 3960 J of work on the oars in 60.0 s. What is his power output in watts?

8. Using a jack, a mechanic does 5350 J of work to lift a car 0
Using a jack, a mechanic does 5350 J of work to lift a car m in 50.0 s. What is the mechanic’s power output?