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WorksheetsCh. 14 & 15 Test Review
Total questions: 35
Worksheet time: 21mins
Energy and work are measured in the SI unit _________________.
Joules (J)
Newtons (N)
m/s
kg * m/s
If the ____________________ of an object doubles, its kinetic energy doubles.
velocity
force
mass
gravity
The sum of the kinetic energy and potential energy of an object is called its __________________ energy.
potential
mechanical
kinetic
thermal
Figure 15-1In Figure 15-1, the kinetic energy of the pendulum bob decreases between locations B and ____________________.
E
C
A
None
work is a transfer of....
motion
mass
force
energy
Which of the following increases when an object becomes warmer?
chemical energy
elastic potential energy
thermal energy
nuclear energy
The energy stored in gasoline is...
chemical energy
mechanical energy
electromagnetic energy
nuclear energy
Which of the following statements is true according to the law of conservation of energy?
Energy cannot be created.
Energy cannot be destroyed.
Energy can be converted from one form to another.
all of the above
If no friction acts on a diver during a dive, then which of the following statements is true?
The total mechanical energy of the system increases.
Potential energy can be converted into kinetic energy but not vice versa.
(KE+ PE)beginning = (KE + PE)end
all of the above
What is transferred by a force moving an object through a distance?
energy
force
mass
motion
Figure 15-1The kinetic energy of the pendulum bob in Figure 15-1 increases the most between locations
A and B.
A and C.
B and D.
C and D.
Fossil fuels currently account for the majority of the world’s energy use because they are...
distributed evenly throughout the world.
nonpolluting.
renewable energy resources.
relatively inexpensive and readily available.
A drawback of solar energy is that it...
cannot be converted directly into electrical energy.
depends on the climate.
produces water pollution.
is not a renewable resource.
The energy of motion is called...
kinetic energy
potential energy
thermal energy
work
A small 42-kilogram canoe is floating downriver at a speed of 1 m/s. What is the canoe’s kinetic energy? KE = 21mv2
21 J
42 J
84 J
22 J
A mass of 5 kg is taken from the ground to the height of 4 m. Find the potential energy of the object. PE = mgh
160 J
20 J
400 J
200 J
Which of the following is an example of an object with elastic potential energy?
a wind-up toy that has been wound up
a compressed basketball
a stretched rubber band
all of the above
A machine is a device that changes a(an) ____________________.
amount of energy
force
measurement
weight of an object
The force that is exerted on a machine is called the ____________________ force, while the force that is exerted by a machine is called the _____________________ force.
input, output
output, input
input, strong
Newton, output
The ______________________ of a machine is the number of times that the machine increases the input force.
input advantage
output force
input distance
mechanical advantage
The mechanical efficiency of any machine is always ____________________ 100 percent.
less than
equal to
greater than
less than or equal to
greater than or equal to
Figure 14-1The bottle opener shown in Figure 14-1 is a(an) ____________________-class lever.
first
second
third
none of the above
Two or more simple machines working together make up a(an) ____________________ machine.
combination
simple
compound
complex
In which of the following is no work done?
lifting a book
climbing stairs
pushing a shopping cart
none of the above
How can a machine make work easier for you?
by decreasing the amount of work you do
by changing the direction of your force
by increasing the work done by the machine
none of the above
If you know the input distance and output distance of a machine, which of the following can you calculate?
work
actual mechanical advantage
efficiency
ideal mechanical advantage
What is the net force acting on the following object? The positive direction is to the right.
700 N
900 N
780 N
820 N
The efficiency of a machine is always less than 100 percent because
a machine cannot have an IMA greater than 1.
the work input is too small.
some work input is lost to friction.
the work output is too great.
Which of the following are simple machines? Check all that apply.
crowbar
screw
inclined plan
lever
pulley
The ideal mechanical advantage of a pulley system is equal to the
distance the load has to move.
length of the rope.
number of rope segments supporting the load.
weight of the object being lifted.
If you exert a force of 15 N to lift a box a distance of 2 m, how much work do you do?
300 J
17 J
7.5 J
30 J
If you exert a force of 250 N to walk 3 m up a flight of stairs in 10 s, how much power do you use?
75 W
750 W
8.3 W
833.3 W
If you have to apply 50 N of force on a crowbar to lift a rock that weighs 200 N, what is the actual mechanical advantage of the crowbar?
10,000
4
20
150
A 300-m long ski lift carries skiers from a station at the foot of a slope to a second station 75 m above. What is the IMA of the lift?
225
1
100
4
A mechanical device requires 480 J of work to do 120 J of work in lifting a crate. What is the efficiency of the device?
25%
40%
50%
100%
