Work
KE
PE
Cons. of Energy
Power
100
In order for work to be done, what must be true of force and displacement
they cannot be zero
100
if an object is not moving it has _____ KE
0
100
Potential energy is the energy due to ____
position
100
When is mechanical energy conserved?
when there is no friction
100
The unit for power is called the
Watt. Know the other forms.
200
If the sign of work is positive, this means that .....
force and displacement are in opposite directions. Example: friction, moving against gravity
200
the formula for kinetic energy is
1/2 mv^2
200
The work done lifting an object is _____ its change in potential energy
equal to
200
Which of the following is a form of mechanical energy a. Internal b. Electrical c. Chemical potential d. Gravitational potential
D
200
If a job done two different ways requires the same amount of work, how is power affected
depends on the time
300
a car slows down on a flat road; is work being done?
yes, negative work
300
Ball A has double the mass of ball B. What is the ratio of KE of A to B
2:1
300
What are the units for potential energy?
Joules
300
Friction converts kinetic energy to ___
Heat
300
The distance an object is pushed doubles while the time it takes to do the work is cut in half, what happens to the power
4 times greater
400
What is the unit of Work
Joules, N*m or Kgm^2/s^2
400
If the velocity of an object triples its KE will be
nine times greater
400
Potential energy is always measured relative to _____
an arbitrary zero level
400
if friction is negligible, the what will be the kinetic energy of an arrow that is shot out of a bow that has a potential energy of 70 J
70 J
400
If the power an object has triples what will happen to its speed
it will triple
500
If speed is constant during the motion, will work be done?
Yes, think of moving against gravity.
500
If friction is the only force acting on an object will its KE will?
decrease
500
if the height of an object off the ground is cut in half, its potential energy would be _________
1/2
500
Energy is changed from one form to another. Therefore, all of the food you eat is turned into:
heat and movement.
500
The kilowatt-hour is a measure of _____
Energy usage
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