Download Simple Machines - Miss Woods` Class

Mechanical Systems Review
1.
Labeled Diagrams
a. Inclined Planes: Probably the simplest of all machines is the inclined
plane. Any sloping smooth surface may be used as an inclined plane.
Draw a diagram, labeling input distance, effort force, load force, and
output distance.
b. Pulleys: There are two types of pulley systems, which may function alone
or in combinations. Draw and label two diagrams, one illustrating a fixed
pulley, and one illustrating a movable pulley.
c. Levers: There are three distinct types of levers:

Class 1 – this is the only one where the fulcrum is between the
load and the effort force. A first class lever can produce either a speed or
force advantage.

Class 2 – this is the only one where the load force is between the
fulcrum and the effort force. A second class lever produces a force
advantage only.

Class 3 – this is the only one where the effort force is between the
load and the fulcrum. A third class lever produces a speed advantage
only.
Draw and label a diagram of each of the three levers.
d. Wheel and Axle: A wheel and axle is simple two circles or wheels, one
inside the other. A wheel and axle will give you a force advantage if the
effort is applied to the wheel or to a large handle, and a speed advantage if
the effort is applied to the axle. Draw and label two diagrams, one of a
wheel and axle with a speed advantage and one of a wheel and axle with a
force advantage.
2.
Gears: There are three main types of gear trains: reducing gears, parallel gears
and multiplying gears. Draw 3 diagrams, one of each type of gear trains. Label
the driver gear and the driven gear on each diagram.
3.
Pneumatics and Hydraulics:
a. Draw and label a diagram of a hydraulic lift.
b. Write the formula that is used to solve hydraulics problems
c. Using a hydraulic jack, you are able to exert a force of 400 N on an input
(effort) piston with an area of 10m2. What would the area of the output
(load) piston have to be if you wanted to lift a load of a 20 000 N?
d. Write the pressure formula.
e. Your head exerts a force of about 50 N on the steering wheel during a
collision. Approximately 0.00003m2 of your head impacts the steering
wheel. Calculate the pressure of your head hitting the steering wheel.
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4.
Formulas: For each of the following quantities, write the formula that is used to
calculate it
a. Work
b. MA
c. Theoretical MA of levers
d. Efficiency
e. Gear ratio
5.
Units: For each of the following quantities, write the unit or units that it is
measured in
a. Work
b. Force
c. distance
d. MA
e. Load force
f. Effort force
g. Efficiency
h. Work input
i. Work output
j. Pressure
k. Area
l. Gear ratio
6.
Problems: For each of the following examples calculate:
Work input, Work output, Efficiency, and Mechanical advantage and
determine whether it is a speed or force advantage
a. You push a 600N box up a ramp that is 10m long. The ramp is 5m high,
and you put in 350N of effort.
b. You use a first class lever with a load of 20N. The effort force is 10N.
The load is moved 1 m and the effort is moved 2.5 m.
c. A second class lever with a load of 50N is lifted with an effort of 25N.
The load is moved 5 m and the effort is moved 20m .
d. A batter swings a baseball bat with a force of 200N. The baseball has a
weight of 10N. The ball travels 10 m while the batters arm moves 1m.
e. You use a fixed pulley to lift a 10N load 1m up. You apply 10N of effort,
and pull the string 1m.
f. You use a movable pulley to lift a 4N pail up 1m. You apply a force of
2N and pull the rope 3m.
g. At the end of a day at the lake, you put your boat on the trailer. Your
winch has a handle length of 5m and you apply a force of 50N. Your boat
is 20 000 N, and the radius of the axle is 0.01m. You turn the handle 20
times to get your boat up on the trailer.
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7. Gear Calculations: Complete the following chart: (on separate sheet of paper)
# of
# of
Gear Ratio
Gear Ratio
Type of
Type of Gear
teeth
teeth
Calculation
final answer Advantage
Train
on
on
(show work)
(round to
(speed,
(reducing,
Driver Driven
two decimal force or no) multiplying or
Gear
Gear
places)
parallel)
36
26
20
40
14
12
4
12
16
40
8.
Definitions: Write definitions in your own words for the following words:
a. Mechanical advantage
f. Pneumatic system
b. Efficiency
g. Hydraulic system
c. Subsystem
h. Pascal’s law
d. Potential energy
i. Manipulated variable
e. Kinetic energy
j. Responding variable
9.
Energy conversion: for each of the following situations, describe the energy
source and energy product.
a. Dam uses falling water to produce electricity
b. Calculator uses the suns energy to produce electricity
10. Explain how each of the following has influenced technological development
a. Science
c. Safety
b. Trial and error
d. Society
11. Name the six criteria for evaluating a mechanical device and explain how you
might use these criteria when purchasing an item of your choice (e.g. ipod, car,
computer,or
bike)
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