Name________________________________________Period__________Date____________________
Machines and Work Notes
Working Hard or Hardly Working?
1. The scientific definition of work is: the ____________________to an object by a __________ that
makes an object ________________________________________.
2. Applying a force doesn’t always result in _________ being done.
Is Work Being Done?
Situation
Work Done?
Yes or No
Explanation
3. A student leans against the wall in the
hallway while talking to a friend.
4. Pulling a wagon full of puppies.
5. A body builder lifting 500 pounds
above his head.
6. A body builder is holding 350 pounds
above her head.
7. Your car is stuck in the snow. You push
and push but the car doesn’t move.
You are exhausted and sweaty.
How Do You Calculate Work?
8. The equation for calculating work is:
Work = _______________ x _______________
9. The unit for force = ____________________
10. The unit for distance = ____________________
11. The unit for work = ____________________
12. A Newton-meter = ____________________
13. If a group of people move a concrete block 5 meters with a force of 100 N, how much work is
done?
Making Work Easier
14. Read the examples of how machines make work easier. Think of a machine you have used that has
made doing work easier for you. Describe the machine and how it made the work (force x distance)
easier for you.
15. Machines:
a. Can change the amount of _______________ you exert.
b. Can change the _______________ over which you exert a force.
c. Can change the _______________ in which you exert a force.
d. Do __________ change the amount of work done!
Force-Distance Trade-off
Study the arrows drawn next to the simple machines.
Machine
Wheel Barrow
Describe how the machine
makes doing the work easier
You use a smaller force (thin green
arrow) to lift a heavy load (thick
purple arrow)
Explain the “trade-off”
You have to use the small force over
a larger distance (compare the
length of the arrows)
16. Hammer
17. Single Fixed Pulley
18. Screw Driver to
Open Paint Can
Work Output Can Never Be Greater Than Work Input
19. Climbing a Hill: If you want to get to the finish flag, point C, you have two options:
a. start at A and go straight up to the flag,
b. or start at B and walk up the slope to the flag.
Which requires less work? Explain.
Machines make work easier; machines do NOT change the total amount of work done.
20. If a machine allows you to apply a smaller force the distance you apply the force will increase.
Draw an example.
21. If a machine requires a larger force over a small distance, you get distance and/or speed out of the
machine.
Draw an example.
22. If a machine allows you to apply a force in a different direction it might not change how much force
you have to apply or how far you move it.
Draw an example.
Mechanical Advantage
23. Mechanical Advantage = MA =
24. Think about a machine in terms of
a. ____________________ = the force you apply
b. ____________________ = force lifted, force that comes out of the machine.
25. A machine’s mechanical advantage tells you how many times the machine
__________________________________________________.
26. Which of the following machines has a greater mechanical advantage?
Mechanical Advantage = output force ÷ input force
1. Input force = 50 N; output force = 150 N
MA =
2. Input force = 60 N; output force = 240 N
MA =
3. Force applied to machine = 20 N and machine applies a force of 100 N
MA =
4. Force applied to machine = 40 N and machine applies a force of 120
MA =
Types of Simple Machines:
Lever:
27. _______________ = pivot point
28.
Type of Lever
Drawing
Examples
Mechanical Advantage
Examples
Mechanical Advantage
1st class
2nd class
3rd class
29. Pulley:
Pulley
Description
Fixed Pulley:
Moveable Pulley:
Drawing
30. Wheel and Axle:
Wheel & Axle
Description
Drawing
Examples
Mechanical Advantage
31. Inclined Plane:
Inclined Plane
Description
Drawing
Examples
Mechanical Advantage
32. Wedge:
Wedge
Description
Drawing
Examples
Mechanical Advantage
33. Screw:
Screw
Description
Drawing
Examples
Mechanical Advantage
Compound Machines
34. Compound machines are made of two or more _______________ machines.
35. List the simple machines found in these common compound machines.
Compound Machine
Types of simple machines that make it up:
Stapler
Bicycle
36. How are simple machines an important part of your life?
Give examples written in at least two COMPLETE sentences.