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Tue Jan 31 Today Review hw 5.5 Read p293-295 (p280) 83,87,91 (p307-9) 56, 61,76,81,82 ch 10-11 test next Tue. or Wed.!. The formula for kinetic energy is:. K=(mv 2 )/2 K=( mv ) 2 /2 K=2mv 2 K=(mg)/h. 0 of 30. The SI units for energy and work are:. Newtons Watts Joules Amperes. - PowerPoint PPT Presentation
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Tue Jan 31 Today Reviewhw 5.5 Read p293-295
(p280) 83,87,91 (p307-9) 56, 61,76,81,82
ch 10-11 test next Tue. or Wed.!
The formula for kinetic energy is:
K=(mv2)/2
K=(mv)2/2
K=2mv2
K=(mg)/h
0% 0%0%0%
1. K=(mv2)/22. K=(mv)2/23. K=2mv2
4. K=(mg)/h
0 of 30
The SI units for energy and work are:
Newtons
Watts
Joules
Amperes
0% 0%0%0%
1. Newtons2. Watts3. Joules4. Amperes
0 of 30
Kinetic energy is a ____ quantity
Tensor
Scalar
Vector
Negative
0% 0%0%0%
1. Tensor2. Scalar3. Vector4. Negative
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The transfer of energy by mechanical means is called _______.
Heat
Mach
ination W
ork Fo
rce
0% 0%0%0%
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1. Heat2. Machination3. Work4. Force
Work is done when:
A force
acts t..
.
A hot object
t...
A force
acts p...
You sleep on t..
.
0% 0%0%0%
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1. A force acts through a distance.
2. A hot object touches a cold object.
3. A force acts perpendicular to a displacement
4. You sleep on the job.
Energy stored in an object that has been lifted in a gravitational field is called:
Elasti
c potent...
Gravita
tional ...
Chemical p
oten...
Thermal e
nergy...
0% 0%0%0%
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1. Elastic potential energy
2. Gravitational potential energy
3. Chemical potential energy.
4. Thermal energy.
If an object’s speed doubles its kinetic energy:
Quadruples
Doubles
Is cu
t in half..
.
Doesn’t c
hange
0% 0%0%0%
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1. Quadruples2. Doubles3. Is cut in half.4. Doesn’t change
The kinetic energy of a 4.0 kg object moving at 3.0 m/s is:
12 J 18 J
36 J 48 J
0% 0%0%0%
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1. 12 J2. 18 J3. 36 J4. 48 J
How much work is done if you push a 5.0 kg box 12 meters across the floor while
applying a 10.0 N force?
50 J 60 J
120 J 600 J
0% 0%0%0%
0 of 30
1. 50 J2. 60 J3. 120 J4. 600 J
How much work do you do if you lift a 6.0 kg object 50 cm up?
None 3.0 J
30 J
3.0 kJ
0% 0%0%0%
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1. None2. 3.0 J3. 30 J4. 3.0 kJ
_____ describes how quickly energy is transferred.
Kinetic energy
Velocity
Power
Pressure
0% 0%0%0%
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1. Kinetic energy2. Velocity3. Power4. Pressure
The SI units of power are:
Joules
Teslas
Pascals
Watts
0% 0%0%0%
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1. Joules2. Teslas3. Pascals4. Watts
A Watt is equal to
N m J s
N/m2 J/
s
0% 0%0%0%
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1. N m2. J s3. N/m2
4. J/s
I have 1.2 kW microwave. How much electrical energy is converted if I heat something on high for 30 seconds?
40 J 400 J
600 J 36 kJ
0% 0%0%0%
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1. 40 J2. 400 J3. 600 J4. 36 kJ
If the power output of a motor is 65 W, how long does it take to do 195 J of work?
1.95 seco
nds
3.0 seco
nds
260 seco
nds
3.5 hours
0% 0%0%0%
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1. 1.95 seconds2. 3.0 seconds3. 260 seconds4. 3.5 hours
________ is where we decide to set gravitational potential energy to zero.
The null zone
Outer space
The reference
...
On top of s
pag...
0% 0%0%0%
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1. The null zone2. Outer space3. The reference level4. On top of spaghetti
Which of the following is a conservative force?
Fricti
on
Thrust
Gravity
Air resis
tance
0% 0%0%0%
1. Friction2. Thrust3. Gravity4. Air resistance
0 of 30
A 4.0 kg object is moving has 72 J of kinetic energy when it is 3.0 m above the reference level. Its speed is
2.0 m/s
5.0 m/s
6.0 m/s
192 m/s
0% 0%0%0%
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1. 2.0 m/s2. 5.0 m/s3. 6.0 m/s4. 192 m/s
A 4.0 kg object has 72 J of kinetic energy when it is 3.0 m above the reference level.
Its total mechanical energy is
0.0 J 72 J
120 J 192 J
0% 0%0%0%
0 of 30
1. 0.0 J2. 72 J3. 120 J4. 192 J
A 4.0 kg object has 72 J of kinetic energy when it is 3.0 m above the reference level. Once it falls down to the reference level it will have a kinetic
energy of
72 J 120 J
192 J 0.0 J
0% 0%0%0%
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1. 72 J2. 120 J3. 192 J4. 0.0 J
Simple machines can NOT
Multiply th
e f...
Multiply th
e w...
Change the dir..
.
Change the sp
e...
0% 0%0%0%
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1. Multiply the force that is exerted
2. Multiply the work that is done
3. Change the direction a force is exerted
4. Change the speed
The mechanical advantage of a simple machine describes
How much
the m
...
How much
the d...
How much
the f..
.
How much
the p...
0% 0%0%0%
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1. How much the machine multiplies the work you do
2. How much the distance is multiplied
3. How much the force is multiplied
4. How much the power is multiplied
The efficiency of a machine describes:
The ratio of th
e output...
The ratio of th
e output f.
..
The ratio of th
e output ..
.
0% 0%0%
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1. The ratio of the output work to the input work
2. The ratio of the output force to the input force
3. The ratio of the output distance to the input distance
If a machine has a mechanical advantage of 5.0 how much force must you exert to lift a 60 kg object?
60 N 120 N
300 N 3.0 kN
0% 0%0%0%
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1. 60 N2. 120 N3. 300 N4. 3.0 kN
An input of 8.0 kJ of work is is provided to a machine that exerts a 2.0 kN force through a distance of 3.0
meters. What is the efficiency?
25%37.50%
75%133%
0% 0%0%0%
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1. 25%2. 37.5 %3. 75%4. 133%
A pulley is used to raise a 2.0 kg object 50 cm off of the table. The work done BY the machine is:
1.0 kJ 100 J
10.0 J 1.0 J
0% 0%0%0%
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1. 1.0 kJ2. 100 J3. 10.0 J4. 1.0 J
A pulley is used to raise a 2.0 kg object 50 cm off of the table. The person pulling the string exerts a force of 8.0 N through a distance of 2.0 m. How much work is done
by the person?
1.0 J
10.0 J 4.0 J
16 J
0% 0%0%0%
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1. 1.0 J2. 10.0 J3. 4.0 J4. 16 J
A pulley is used to raise a 2.0 kg object 50 cm off of the table. The person pulling the string exerts a force of 8.0 N through a distance
of 2.0 m. The mechanical advantage of the machine is
4.2.5 2. .5
0% 0%0%0%
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1. 4.02. 2.53. 2.04. 0.50
A pulley is used to raise a 2.0 kg object 50 cm off of the table. The person pulling the string exerts a force of 8.0 N through a distance
of 2.0 m. The efficiency of the machine is
31%63%
100%160%
0% 0%0%0%
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1. 31%2. 63%3. 100%4. 160%
A pulley is used to raise a 2.0 kg object 50 cm off of the table. The person pulling the string moves their hand
2.0 m. What is the IMA of the machine?
4.2.5 .25 10.
0% 0%0%0%
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1. 4.02. 2.53. 0.254. 10.0