Post on 02-Feb-2022
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Simple Machine Quiz Review
1.
List and explain the mechanical advantage of the 6 simple
machines.
Lever Inclined Plane
MA =Length to Effort (LE)/Length to Load (LR)
MA =Length of Plane (L)/Height of Plane (H)
Wheel and Axle Pulley
MA =Radius of Effort (LE)/Radius of Load (LR)
MA =number of ropes that support the pulley
Wedge Screw
MA =
Length of slope (L)/thickness of wedge (H)
MA =
Circumference (C) / pitch (p)
2. Draw and identify parts of the simple machines.
Lever Input force
Output force
Effort force
Resistance force
Fulcrum
MA = effort distance/resistance distance
MA = resistance force/effort force
Incline plane
Weight = output force
Res
ista
nc
e d
ista
nc
e
MA = effort distance/resistance distance
MA = resistance force/effort force
Pulley
Input force
Weight = output forceEffort distance
Resistance distanceMA = effort distance/resistance distance
MA = resistance force/effort force
MA = numbers of support on the weight
Wheel and Axle
Radius of the wheel
effort distanceRadius of the axle
resistance distance
Effort force
Weight = resistance force
MA = radius of the wheel/radius of the axle
MA = resistance force/effort force
SCREW
WEDGE
3.
How do machines make doing work easier?
Machines can either multiply the input force and change the
direction of the input force.
4.
What is the cost for making work easier?
The cost is distance over which the input force is applied.
5.
Even though machines make work easier. What can a machine
not do?
Machines cannot increase or decrease the amount of
work/energy in a system.
6. Given a 4-meter long incline, what is the height in which the
incline must be placed to get a mechanical advantage 4? 2?
and 1?
The MA of an incline is
MA = length of the slope/the height of the incline.
4 = 4/h → h = 1 meter
2 = 4/h → h = 2 meters
1 = 4/h → h = 4 meters
7.
A screw that has 5 threads per cm. If a screwdriver has a radius
of 1.25 cm, then what is the mechanical advantage of the
screwdriver?
MA = circumference of the handle/pitch
MA = 2p(1.25) / (1/5)
MA = 12.5p = 39.3
8.
Explain the difference between IMA and AMA.
Ideal Mechanical Advantage
1. a. A simple machine would be considered ideal if it had no friction that’s because some of the effort that is put into the machine is wasted in overcoming friction.
b. Ideal Mechanical Advantage has the symbol IMA.
c. Ideal Mechanical Advantage can be determined by the following equation:
ideal mechanical advantage =
Actual Mechanical Advantage
2. a. Actual machines have friction. They are not as have as high of a mechanical advantage as ideal machine because some of the effort is lost in overcoming friction. b. Actual Mechanical Advantage has the symbol of AMA.
c. Actual Mechanical Advantage can be determined by the following equation: actual
R
E
d
d==
ramp ofheight
ramp oflength
distance resistance
distanceeffort
F
F
forceinput
forceoutput
forceeffort
force resistance
E
R===AMA
9.
What do the IMA and AMA have to do with how efficient a
machine is?
The ratio of AMA to IMA times 100 gives the percentage of
efficiency of a machine.
EfficiencyIMA
AMA=100
10.
If two students were playing on a seesaw and one student has
twice the mass of the other student, explain how to balance
the two students on the seesaw.
The heavier student would be place half of the distance to the
fulcrum as the lighter student or
the lighter student placed twice the distance to the fulcrum
as the heavier student.
5 m 10 m
50 kg 25 kg
Mgd = mgD
Md = mD
50 (5) = 25 (10)
250 J = 250 J
11.
Explain why having a load at the furthest end from the fulcrum
of a lever make it an inefficient system of using a lever.
100 N
50 m
25 m
200 N
JJ
FdFd
500500
)50(100)25(200
=
=
=
12.
A lever used to lift a heavy box has an input arm of 4 meters
and an output arm of 0.8 meters. What is the mechanical
advantage of the lever?
12.
A lever used to lift a heavy box has an input arm of 4 meters
and an output arm of 0.8 meters. What is the mechanical
advantage of the lever?
58.0
4===
r
e
d
dMA
13.
What is the mechanical advantage of a lever that has an input
arm of 3 meters and an output arm of 2 meters?
13
What is the mechanical advantage of a lever that has an input
arm of 3 meters and an output arm of 2 meters?
5.12
3===
r
e
d
dMA
14.
A lever with an input arm of 2 meters has a mechanical
advantage of 4. What is the output arm’s length?
14.
A lever with an input arm of 2 meters has a mechanical
advantage of 4. What is the output arm’s length?
md
d
d
dMA
r
r
r
e
5.04
2
24
==
=
=
15.
A lever with an output arm of 0.8 meter has a mechanical
advantage of 6. What is the length of the input arm?
15.
A lever with an output arm of 0.8 meter has a mechanical
advantage of 6. What is the length of the input arm?
md
d
d
dMA
e
e
r
e
8.4
8.06
=
=
=
16.
A rake is held so that its input arm is 0.4 meters and its output
arm is 1.0 meters. What is the mechanical advantage of the
rake?
16.
A rake is held so that its input arm is 0.4 meters and its output
arm is 1.0 meters. What is the mechanical advantage of the
rake?
4.0
1
4.0
=
=
=
MA
MA
d
dMA
r
e
17.
A broom with an input arm length of 0.4 meters has a
mechanical advantage of 0.5. What is the length of the output
arm?
17.
A broom with an input arm length of 0.4 meters has a
mechanical advantage of 0.5. What is the length of the output
arm?
md
d
d
dMA
r
r
r
e
8.0
4.05.0
=
=
=
18.
A child’s toy rake is held so that its output arm is 0.75 meters.
If the mechanical advantage is 0.33, what is the input arm
length?
18.
A child’s toy rake is held so that its output arm is 0.75 meters.
If the mechanical advantage is 0.33, what is the input arm
length?
md
d
d
dMA
r
r
r
e
2475.0
75.033.0
=
=
=
19.
A 5-meter ramp lifts objects to a height of 0.75 meters. What is
the mechanical advantage of the ramp?
19.
A 5-meter ramp lifts objects to a height of 0.75 meters. What is
the mechanical advantage of the ramp?
md
MA
d
dMA
r
r
e
67.6
75.0
5
=
=
=
20.
A 10-meter long ramp has a mechanical advantage of 5. What is
the height of the ramp?
20.
A 10-meter long ramp has a mechanical advantage of 5. What is
the height of the ramp?
md
d
d
dMA
r
r
r
e
2
105
=
=
=
21.
A ramp with a mechanical advantage of 8 lifts objects to a
height of 1.5 meters. How long is the ramp?
21.
A ramp with a mechanical advantage of 8 lifts objects to a
height of 1.5 meters. How long is the ramp?
md
d
d
dMA
e
e
r
e
12
5.18
=
=
=
22.
A child makes a ramp to push his toy dump truck up to his
sandbox. If he uses 5 newtons of force to push the 12-newton
truck up the ramp, what is the mechanical advantage of his
ramp?
22.
A child makes a ramp to push his toy dump truck up to his
sandbox. If he uses 5 newtons of force to push the 12-newton
truck up the ramp, what is the mechanical advantage of his
ramp?
4.2
5
12
=
=
=
MA
MA
F
FMA
e
r
23.
A ramp with a mechanical advantage of 6 is used to move a 36-
newton load. What input force is needed to push the load up
the ramp?
23.
A ramp with a mechanical advantage of 6 is used to move a 36-
newton load. What input force is needed to push the load up
the ramp?
NF
F
F
FMA
e
e
e
r
6
366
=
=
=
24.
Gina wheels her wheelchair up a ramp using a force of 80
newtons. If the ramp has a mechanical advantage of 7, what is
the output force (in newtons)?
24.
Gina wheels her wheelchair up a ramp using a force of 80
newtons. If the ramp has a mechanical advantage of 7, what is
the output force (in newtons)?
NF
F
F
FMA
r
r
e
r
560
807
=
=
=
25.
Challenge! A mover uses a ramp to pull a 1000-newton cart up
to the floor of his truck (0.8 meters high). If it takes a force of
200 newtons to pull the cart, what is the length of the ramp?
25.
Challenge! A mover uses a ramp to pull a 1000-newton cart up
to the floor of his truck (0.8 meters high). If it takes a force of
200 newtons to pull the cart, what is the length of the ramp?
md
d
d
dMA
MA
N
NMA
F
FMA
e
e
r
e
e
r
4
8.05
5
200
1000
=
=
=
=
=
=