Name:___________________________
Work-
Simple Machine Quiz Study Guide
1.) What is one of the definitions for work?
Moving something with a force, or when a force is applied through a distance or
energy transfer through motion.
2.) What is the formula for work?
Work= Force • Distance
3.) What is the unit for work?
Joule
(N•M)
Simple Machines in General1.) What are the 6 types of simple machines?
Inclined plane, lever, pulley, wheel and axle, screw & wedge
2.) What are the 2 basic types of simple of machines, of which all other simple machines are
variations of?
Inclined Plane & Lever
3.) In general, what do simple machines do? What is their purpose?
Simple machines make work easier by reducing the force needed to do the
same amount of work
4.) When we talk about work being “easier,” what do we mean by “easier work?”
Less force required to do work
5.) A force applied by a machine to an object is the?
a.) resistance force
b.) effort force
6.) A force applied to a machine by a person is the?
a.) resistance force
b.) effort force
c.) force field
c.) force field
Inclined Plane
1.) Draw an inclined plane in the space below and label the effort distance and resistance
distance?
2.) An inclined plane reduces
distance
the force needed to lift an object by increasing the
that force is applied.
3.) If it takes 45343 joules of work to lift a barrel into the back of a truck without using a
simple machine, how much work would be required to get the barrel into the back of the truck
using a ramp that is 4m long?
b.) more than 45343 Joules
c.) 45343 Joules
Why? Simple machines never lower the amount of work, they only lower the force
required to do the work, HOWEVER they can, because of friction, actually make
more work
a.) less than 45343 Joules
4.) If the force required to lift a barrel into the back of a truck was 124 Newtons, what would
the force required to get the barrel into the back of the truck using a ramp that is 4m long?
a.) less than 124 Newtons
b.) more than 124 Newtons
c.) 124 Newtons
Why? Simple machines make work easier by reducing the force needed to move an object
5.) What did the experiment on page 4 prove?
Using a simple machine reduces the force needed to move an object by increasing the
distance of the force, HOWEVER does not change the total amount of work
Lever
1.) Explain, in detail, how you would determine what class a lever is?
“The longer the arm of the lever to which force is applied, the less that
force need be”
2.) What happens to the force needed to move the object as you increase the effort arm by
moving the fulcrum closer to the object.
The force required to lift the weight will DECREASE
3.) Would Machines with higher mechanical advantage would take more or less effort force to
make something move? A.) more
b.) Less
c.) the same
4.) Would machines with higher mechanical advantage would take more or less work to make
something move?
A.) more
b.) Less
c.) the same (because of Friction)
5.) True or False and explainALL LEVERS make work easier
False- Third class levers do not make work easier, they give you
increased speed.
6.) Label the effort, resistance and fulcrum in the pictures below an identify what class of
lever it is.
Mechanical Advantage
1.) What is mechanical advantage? What does this tell us? (do not give formula, actually tell
me what it is) The number of times a machine multiplies an effort force. It tells us
how much easier a machine makes the work
2.) What is the difference between Ideal Mechanical Advantage and Mechanical Advantage.
Ideal mechanical advantage does not take friction into account.
3.) Why do we look at the distance something travels rather than the force required with
Ideal Mechanical Advantage?
a.) looking at the distance is more accurate because it does not require force meters
b.) looking at the distance eliminates friction
c.) looking at the distance helps us measure the force
d.) looking at the distance is easier because Mr. Strelick said so
Pulley
1.) What are the three types of pulleys?
Single moveable, single fixed and block & tackle
2.) How do you find the mechanical advantage of a pulley?
Count how many sections of rope are supporting the weight.
3.) True or False and explain-
ALL PULLEYS make work easier
False, fixed pulleys do not make work easier, they only change
direction of the force.
4.) Find the effort force required to lift the 300 N weight in the diagrams below.
Summary
1.) Simple machines make work easier, however there are 2 exceptions to this rule. What are
the exceptions, and in each case, what is the “advantage” each machine gives us.
Single fixed pulley- change direction
3rd class levers- give you increased speed
2.) Group the following words/phrases into 2 categories:
Work in
Work out
Resistance
“Work done TO THE machine”
Work in, Effort, input
Effort
output
input
“Work done BY THE machine”
Work out, Resistance,
output
Wheel and Axle1.) The wheel and axle is most like which type of simple machine?
a.) lever
b.) inclined plane
2.) Which part of the wheel best represents the effort force? (large or small)
Large Wheel
3.) what part of the wheel best represents the resistance force?
Axle
4.) What would be easier (take less force) to turn and why:
An axle with a diameter of 10cm using a 100cm wheel
An axle with a diameter of 10cm using a 50cm wheel
It has a larger effort wheel (large wheel). When you increase the
effort distance, you decrease the effort force.
Why-
5.) What would require the least amount of work to turn and why:
An axle with a diameter of 10cm using a 100cm wheel
An axle with a diameter of 10cm using a 50cm wheel
Both amounts of work are the same due to the axles being the same.
The 100cm wheel would just be easier because it travels a greater distance.
Why-
The Screw1.) The screw is most like which type of simple machine?
a.) lever
b.) inclined plane
2.) What specifically are the arrows in the picture to the right pointing to?
Threads
Use the picture below to answer #3-5
3.) Which of the above screws (A or B) would require the greatest amount of force to drive
into a piece of wood?
a.) A
b.)B
Why There are less threads so there is less distance. There is MORE force required for
the screw with less distance (threads)
4.) Which of the above screws (A or B) would be the easiest to drive into a piece of wood?
a.) A
b.)B
Why
There are more threads so there is more distance. Since the rule is the greater the distance
the less the force, there is LESS force required for the screw with more distance(threads)
5.) Which of the above screws (A or B) would have the greatest mechanical advantage?
a.) A
b.)B
The Wedge
.) The wedge is most like which type of simple machine?
a.) lever
b.) inclined plane
2.) What does the wedge do as it moves into a material?
Separates them
3.) What are two examples of a wedge?
Axe, Knife
4.) Of the two wedges to the right, which do you think would require the
least amount of force if you wanted to separate those objects 8cm?
Wedge B
Why?- Wedge B has a greater distance (length) and the rule is when you increase the
distance, you decrease the force (make work easier)
Using Simple Machines
1.) What is a compound machine?
A combination of 2 or more simple machines
2.) What is the formula for efficiency?
3.) Simple machines make work easier, but they actually make more work.
Explain how this true, how can they make more work yet make the work easier?
Simple machines make the work easier by decreasing the force needed to do
something. They do this by increasing the distance that force is applied.
Although the work is getting easier, the total amount of work is actually
increasing due to friction.
Power
1.) 1.) What is the definition of power
The amount or rate of work done in a certain amount of time
2.) What is the formula for power?
Power=work/time
Units
1.) What is the unit for each of the following?
Energy: Joules
Work: Joules or Newton/Meters
Power: Watts or Joules/second
Mechanical advantage: no unit
Efficiency: %
True or False and Explain!
1.) In general, simple machines make less work? False, simple machines make
work easier but do not reduce the total amount of work needed.
2.) In general, simple machines make work easier? True, simple machines reduce
the force needed to make something move. They do this by
increasing the distance the force is applied
3.) Single moveable pulleys make work easier? True, It is the single FIXED
pulley that does not make the work easier
4.) All types of levers make work easier?
False- Third class levers do not make work
easier, they give you increased speed.
Calculations: Show your work
A clown is trying to lift a refrigerator full of wigs a height of
2M. It would take him a force of 60 Newtons to lift the fridge without a simple machine.
1.) Exactly How much work would be required to lift this fridge of wigs without a machine?
Work = Force x Distance
Force= 60 N
W= 60 Newtons x 2 M
Work= 120 Joules
Distance= 2 M
2.) Assuming no friction, how much work would be required to lift the fridge of wigs with a
lever that has a mechanical advantage of 6?
120 joules- Using a lever with a M.A of 6 would only make the work easier,
it would not change the total amount of work.
3.) Assuming no friction, how much force would be required to lift the fridge of wigs with a
lever that has a mechanical advantage of 6?
Since the M.A is 6, the force would be 6 times easier. Therefore the force
would be 1/6 of the original force. Therefore the force would be 10 Newtons.
4.) What is the force needed to lift a magic school bus if you use a lever with a mechanical
advantage 25. The force required to lift the dishwasher without a lever would be 1000 N.
MA = 25
FR = 1000N
FE = ?
MA= FR
FE
or
FE = FR FE =1000 N
MA
25
FE = 40 N
5.) How much work is being done by a penguin pushing a purple piano with a force of 50 N up a
ramp that is 8 meters long?
Work = Force x Distance
Force= 50 N
W= 50 Newtons x 8 M
Work= 400 Joules
Distance= 8 M
6.) What is the mechanical advantage if a unicorn uses its horn as a lever, to open door using
300 N of force, which would normally take about 900N to open (without a simple machine).
Resistance= 900 N M.A = Resistance
M.A = 900 N
M.A = 3
Effort= 300 N
effort
300 N
M.A = ?
7.)How much work is required to lift a bag of cat litter 2 meters, if the bag has a force of 40N.
Work = Force x Distance
Force= 40 N
W= 40 Newtons x 2 M
Work= 80 Joules
Distance= 2 M
8.) Melvin the mighty monkey is trying to get a big bag of bananas into his tree house. It takes
90 Newtons of force to lift into a tree without using a simple machine. He then makes the
work easier by putting a ramp up to his tree house, which allows him to move the bag of
bananas with 10 Newtons of force. What is the Mechanical Advantage of this inclined plane?
Resistance= 90 N
M.A = Resistance
M.A = 90 N
M.A = 9
Effort= 10 N
effort
10 N
M.A = ?
9.) What is the Ideal Mechanical Advantage of a lever whose effort arm measures 55cm and
whose resistance arm measures 5 cm?
Resistance= 5 cm
I.M.A= Effort Arm
I.M.A = 55 cm
I.M.A = 11
Effort= 55 cm
Resistance Arm
5 cm
I.M.A Lever = ?
10.) What is the Ideal Mechanical Advantage of an inclined plane that has a length of 400cm
and a height of 50cm
Resistance= 50 cm I.M.A= Effort dist(Length)
I.M.A = 400 cm I.M.A = 8
Resistance dist(Height)
Effort= 400c m
50 cm
I.M.A Lever = ?
11.) What is the ideal mechanical advantage for the object below. Show your work
Radius Wheel= 1.5cm
Radius Axle= 0.3cm
IMA= Radius of Wheel IMA= 1.5cm
Radius of Axle
0.3cm
IMA= 5
12.) What is the ideal mechanical advantage for the object below. Show your work
Radius Wheel= 11cm
Radius Axle= 3cm*
IMA= Radius of Wheel IMA= 11 cm IMA= 3.67
Radius of Axle
3cm
*its 3 because in the picture,
the 6cm represents the
diameter
13.) A mysterious green box is lifted onto the back of a truck that is 2.1M high. If it
takes 500 Joules of work to do this without using a simple machine, what would be the
efficiency of an inclined plane if the force required was 150N over a distance of 4 M?
Work without machine= 500 Joules
Work with machine= W=F • D
150 N • 4m =
600 Joules
Work WITHOUT machine
Work WITH machine
500 Joules x100
600 Joules
83.3%
14.) If you walk up the steps (distance of 4 meters) in 6 seconds, what is your power? Assume
you have a force of 440 N
Power= ?
Power= Work/Time
1760J
293,3
6 seconds
Watts
Work= F x d =440N x 4m =1760J
Time= 6 seconds
15.) What is the ideal mechanical advantage for a lever whose fulcrum is at 20cm?
Resistance= 20cm I.M.A= Effort Arm
I.M.A = 80cm
Effort= 80cm
Resistance Arm
20 cm
I.M.A Lever = ?
I.M.A = 4
Formulas:
Work= Force • distance
Efficiency=
Work
(out) or
Work
(in)
F(resistance) X D(resistance)
F(effort) X D(effort)
X 100%
Power= Work
Time
MA = Resistance Force
or
FR
Effort Force
I.M.A =
Effort Distance
Resistance Distance
FE
or
DE
DR
I.M.A(wheel & Axle) =Radius of wheel or Diameter of wheel
Radius of axle
Diameter of axle