Study Guide – Work, Power & Machines Name:_______________________________________
1. WORK:
a. Define work:
b. Work can also be defined as a transfer of ________________.
c. In order for work to be done, force and displacement must be in the ____________________ direction.
d. Give one example in which work is done:
e. Give one example in which work is not done:
f. For the following 3 scenarios, explain why work is or is not done:
- A woman preparing for a trip lifts her suitcase from the floor to the bed so that she may pack more easily.
- A man spends 5 minutes thinking about the most efficient way to decorate his roof with Christmas lights.
- A student carries his book bag down the hallway.
g. Identify which of the pairs in each scenario illustrates more work being done:
_____ A boy helps a teacher by lifting a 200-N box of books 1.5 meters from the floor to the desktop.
_____ The same boy lifts a 500-N box of books the same height.
Explain your choice:
_____ A girl throws a 1-kg softball with a force of 50 Newtons a distance of 25 meters.
_____ The same girl throws the softball with the same force a distance of 17 meters.
Explain your choice:
h. The formula for calculating work is ______________________, and the unit for work is the ______________.
2. POWER:
a. Define power:
b. How are power and work related?
c. Identify which of the pairs in each scenario illustrates less power being generated:
_____ A woman pushes a cart with 95 N of force 3 m in 10 seconds.
_____ A man pushes a cart with 95 N of force 3 m in 13 seconds.
Explain your choice:
_____ A 340-N student climbs the stairs in 14 seconds.
_____ A 420-N student climbs the stairs in 14 seconds.
Explain your choice:
d. The relationship between power, force and velocity is ______________________________________________.
3. MACHINES:
a. A machine is a device that _____________________________________________________________________.
b. The 6 simple machines include:
c. The 2 simple machines that are a modified version of the inclined plane are ______________________ and
_______________________.
