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21 questions
A roller coaster whose average speed is 32 m/s is at the top of a 72m hill and weighs 966N. At the top of the hill the coaster car has ___________________ energy.
only kinetic energy
only potential energy
mostly kinetic energy
both kinetic and potential energy
What is the potential energy of a 3kg ball that is on the ground?
0 J
3 J
9.8 J
29.4 J
A weightlifter holds a 100 kg barbell above her head. Is work done?
Yes because there is a force applied to the barbell and the force causes a displacement of the barbell.
Yes because there is an upward force applied to the barbell and the barbell moves vertically.
No because no displacement occurred.
No because there is no force applied.
A 735kg empty roller coaster is at its starting point whose distance from the ground is 150m. After a while, it moves at point B whose distance from the ground is 120m. What is the kinetic energy of the coaster at point B?
1,080,450J
864,360J
216,090J
0J
Which of the following is defined as an energy transfer?
kinetic energy
work
potential energy
chemical energy
A light plastic cart and a heavy steel cart are both pushed with the same force for a distance of 1.0 m, starting from rest. After the force is removed, the kinetic energy of the light plastic cart is ________ that of the heavy steel cart.
greater than
equal to
less than
can't say unless we know how big the force is
Four students run up the stairs in the time shown. Which student has the largest power output?
A
B
C
D
A major league pitcher can throw a baseball with a kinetic energy of 150 J. How much work must the pitcher do to the ball to give it that much KE?
150 J
0
Can’t tell without knowing the mass of the ball
What is the unit for power?
what
watt
joule
Jewel-Osco
Which requires more work – a person walking up stairs or a person running up stairs?
walking
running
they require equal work
no work is required for either because the movement is vertical
Which requires more power – a person walking up stairs or a person running up stairs?
walking
running
they require equal power output
no power is required at all
How much work is done on a 200-kg crate that is hoisted 2 m in a time of 4 s?
400 J
1000 J
1600 J
4000 J
How much power is required to raise a 200-kg crate a vertical distance of 2 m in a time of 4 s?
400 W
1000 W
1600 W
4000 W
An 8-kg object is raised by a crane to the top of a building 20-meters in height. If it takes 50 seconds for the object to get to the top of the building, then how much power was needed?
1600 watts
3.2 watts
32 watts
200 watts
If a light bulb is switched on for 20 s and it consumes 2400 J of electrical energy then it's power is
60 W
70 W
80 W
90 W
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