# Work and Power

```Work and
Power
Assignment
I will number you into groups.
You will be working in chapter 8 of
the book.
Expectations
You will be presenting your section to
class.
The method of presentation is your
choice. (notes, demonstrations, vocab
game…)
Your group will also generate 5 test
questions (multiple guess / calculations)
Work
Work – a force applied over a
distance
W= F(d)
units: F=Newton d=meter
W= Joules
W=Fxd
Therefore:
You must have MOTION in order to
have work… something has to
change position
Power
Power – the rate at which work
is done
Power = Work/time
Unit is Watt (joule/second)
Example Problems
If a 450 N boulder is
dropped 2.4 m in 25
seconds, how much power
is exerted on the object?
Example Problems
How much work is done by a toy
car with an applied force of 12
N which is moved for 39 m?
The weight lifter lifted a mass of 100
kg (barbell) over her head in 5.21
seconds. Approximately how much
power did she generate in raising the
barbell?
Example Problems
A mechanic used a hydraulic lift to
raise a 12,054 N car 1.89 m above
the floor of a garage. It took 4.75 s
to raise the car. What was the
power output of the lift?
```