WorksheetsPower Work Efficiency
Total questions: 20
Worksheet time: 16mins
Name
Class
Date
1.
Work is a measure of the energy needed to apply a force across a _______.
a)
time
b)
distance
c)
gravity
d)
object
2.
Efficiency is a ______ of what you put in versus what you get out of a system.
a)
source
b)
ratio
c)
multiplication
d)
addition
3.
An object has a weight of 200 N and is moved 3 meters. How much work is done?
a)
66.7 J
b)
600 J
c)
203 J
d)
0.015 J
4.
A light bulb consumes 100 Watts. If it is left on for 20 seconds, how much work does it do?
a)
5 J
b)
2,000 J
c)
0.2 J
d)
100 J
5.
For there to be work, there must always be distance.
a)
True
b)
False
6.
Power does not depend on...
a)
strength
b)
work
c)
time
d)
any of these
7.
How much work is done in holding a 15 N sack of potatoes while waiting in line at the grocery store for 3 minutes?
a)
15 J
b)
45 J
c)
0 J
d)
5 J
8.
What is the difference between calculating power and work?
a)
Power takes into account the time it takes to complete a task
b)
Work takes into account the time it takes to complete a task
c)
Power is force/area
d)
Work is force/area
9.
You are pushing a car as hard as you can for 5 minutes, but cannot get it to move. How much work have you done on the car?
a)
There is not enough information to calculate the work.
b)
If you used 20 newtons of force, you will have done 100 Joules of work
c)
None. There was no movement.
d)
None of the answers are correct.
10.
Find the work of a turtle that has a force of 27 newtons and travels a distance of 3 meters.
a)
81 watts
b)
81 joules
c)
9 watts
d)
9 joules
11.
How much power is needed to do 648 Joules of work in 100 seconds?
a)
64800 Joules
b)
64800 watts
c)
6.48 watts
d)
0.15 watts
12.
measures the ratio of work output to work input
a)
joules
b)
power
c)
work
d)
efficiency
13.
What is the efficiency of a machine if 55.3 J of work are done on the machine, but only 14.3 J or work are done by the machine?
a)
0.25 Joules
b)
26%
c)
3.86 Joules
d)
386%
14.
How are work and and power related?
a)
if work is increased than the power generated is decreased
b)
there is not enough information given to know the answer
c)
if work is increased than power is increased
d)
work and power are not related
15.
What units are used to measure power?
a)
watts
b)
Joules
c)
meters
d)
newtons
16.
Consider the following two situations:
1. a girl kicks a ball across a field
2. A boy holds a suitcase by his side.
which of the following responses is correct about the two situations.
1. a girl kicks a ball across a field
2. A boy holds a suitcase by his side.
which of the following responses is correct about the two situations.
a)
Work is done in both situation.
b)
No work is done in either situation.
c)
Work is done in the first situation, but not the second.
d)
work is done in the second situation, but not the first.
17.
A force exerted over a distance to move an object is ______________________.
a)
power
b)
work
c)
momentum
d)
Watt
18.
The efficiency of a machine can be increased by reducing __________________________.
a)
effort
b)
resistance friction
c)
fulcrum
d)
friction
19.
No machine in existence has 100% efficiency due to ____________________.
a)
magic
b)
friction
c)
smoke
d)
input
20.
Work divided by time equals...
a)
energy
b)
power
100 %
