Conservation of Energy Answers

0 verified answers1 views
1
Free Preview

What does the law of conservation of energy state about energy in a closed system?

A
Energy cannot be created or destroyed.
B
Energy can be created but not destroyed.
C
Energy can be destroyed but not created.
D
Energy can be either destroyed or created.
2
Free Preview

Irving, a cat, has a favorite toy that is made up of a squeaky ball at the end of a string. The toy makes up a closed system. Irving’s owner dangles the toy so that the ball swings down and then swings back up again.

A
As the ball moves upward, both kinetic and potential energy decrease.
B
As the ball moves downward, both kinetic and potential energy increase.
C
As the ball moves upward, kinetic energy decreases and potential energy increases.
D
As the ball moves downward, kinetic energy decreases and potential energy increases.
3

Which equation represents the law of conservation of energy in a closed system?

A
KEi + PEi = KEf + PEf
B
PEi + PEf = KEi + KEf
C
KEi – KEf = PEi – PEf
D
KEi – PEf = PEi – KEf
5

What best describes the energy in a closed system at the beginning of a day and the energy at the end of the same day? Check all that apply.Some energy can disappear after it has caused motion.Some energy can be changed from one form to another.Some energy can be lost to the environment around the system.The total initial energy will be equal to the total final energy.The total initial energy will be greater than the total final energy.Friction can cause energy to be destroyed during the day.Friction can cause the amount of thermal energy to increase.

A
Some energy can disappear after it has caused motion.
B
Some energy can be changed from one form to another.
C
Some energy can be lost to the environment around the system.
D
The total initial energy will be equal to the total final energy.
E
The total initial energy will be greater than the total final energy.
F
Friction can cause energy to be destroyed during the day.
G
Friction can cause the amount of thermal energy to increase.
6

A 535 kg roller coaster car began at rest at the top of a 93.0 m hill. Now it is at the top of the first loop-de-loop.This roller coaster’s track is nearly frictionless, so resistance can be ignored. Using g = 9.8 m/s2, what best describes the roller coaster car when it is at the top of the loop-de-loop?

Question illustration
A
The car has only potential energy, so it is moving at 0 m/s.
B
The car has both potential and kinetic energy, and it is moving at 24.6 m/s.
C
The car has both potential and kinetic energy, and it is moving at 34.9 m/s.
D
The car’s potential energy has all been converted to kinetic energy, so it moves at 42.7 m/s.

Did you find these answers helpful?