WorksheetsPower and Effiency
Total questions: 16
Worksheet time: 34mins
Name
Class
Date
1.
If a roller coaster glides to a hill with 50 J of energy and 150 J of energy is lost to friction and heat. How much energy is wasted?
a)
100 J
b)
200 J
c)
50 J
d)
150 J
2.
If a light bulb with an efficiency of 80% lights up the room and 16 J of energy is converted to light energy and 4 J of energy is lost to thermal energy. What is the total energy in the system?
a)
80%
b)
4 J
c)
20 J
d)
16 J
3.
An engine has an inout of 5000 W. The useful output is 4000W. Calculate its percentage efficiency.
a)
90%
b)
80%
c)
75%
d)
85%
4.
Two workers use 100 N of force to move a sofa 2 meters in 2 seconds. How much power is required?
a)
100 watts
b)
400 watts
c)
104 watts
d)
50 watts
5.
If a group of workers can apply a force of 1,000 Newtons to move a crate 20 meters, what amount of work will they have accomplished?
a)
20,000 J
b)
200 J
c)
2,000 J
d)
20 J
6.
If 68 W of power is produced in 18 seconds, how much work is done?
a)
1,224 J
b)
0.264 J
c)
3.77 J
d)
12.24 J
7.
How much time is needed to produce 720 Joules of work if 90 watts of power is used?
a)
0.125 s
b)
8 s
c)
64800 s
d)
80 s
8.
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
9.
W = 500 Joules
t = 25 seconds
P = ???
t = 25 seconds
P = ???
a)
0.05 W
b)
20 W
c)
12500 W
d)
2000 W
10.
What is the unit of measurement for Power?
a)
Joules
b)
Newtons
c)
Watts
d)
Meters
11.
What is power?
a)
transfer a force through a distance
b)
the rate of speed
c)
the rate of work being done
d)
transfer of space over time
12.
What is the equation for work?
a)
W = mass * acceleration
b)
W = force * distance
c)
W = force/distance
d)
W = speed/time
13.
Which of the following is the best example of work being done.
a)
doing homework
b)
lifting a box
c)
pushing a stationary box
d)
holding a box
14.
In which of these cases is work being done?
a)
A student sleeps
b)
A student pushes a locked door that does not move
c)
a student carries his chair into another room
d)
A student sits on the carpet
15.
In which of these cases is work being done?
a)
A student sleeps
b)
A student pushes a locked door that does not move
c)
a student carries his chair into another room
d)
A student sits on the carpet
16.
A kid applies a force of 70 N to a ball over 1.1 meters. How much work did he do on the ball?
a)
77 J
b)
7.7 J
c)
0.7 J
d)
770 J
100 %
