Show:
Work
Power
Potential Energy
Kinetic Energy
Conservation
100
What is the Unit for Work?
Joules (J)
100
What is the unit for power?
Watts
100
What are the units for potential energy?
Joules (J)
100
If the velocity of an object is doubled, what happens to its kinetic energy?
It quadruples!
100
What does the law of conservation of energy state?
Energy cannot be created or destroyed, it just changes forms.
200
If you push an object twice as far without changing the force you pushed it with, what happens to work?
Work doubles!
200
If Mrs. Rohde pushes against the wall with a 50N force for 2 seconds, how much power is she using?
None! No work is done on the wall.
200
What are the three types of potential energy?
Gravitational potential, elastic potential, and chemical potential
200
An object that has kinetic energy must be
Moving
200
As I lift an object higher I do work on the object. As I do work on the object, the objects increases this type of energy.
Potential energy
300
If a business man carries a briefcase with an upward force of 10N a distance 5 m to the right, what is the work he does on the briefcase?
He does 0J of work on the briefcase because the force is perpendicular to his displacement
300
What are two ways that power can be increased?
Increase the amount of work done, or decrease the time in which work is done
300
If you double the height of an object, what happens to its gravitational potential energy?
Gravitational potential doubles as well
300
When does a ball rolling down an incline have maximum kinetic energy?
At the bottom of the incline
300
How do you find the distance a force does work on an object?
Work divided by the force W/F=d
400
In the equation W = F d cos(theta), where is the angle located?
Between the force vector and the displacement vector
400
A 50-kg sack is lifted 2 meters from the ground and a 25-kg sack is lifted 4 meters in the same time. The power expended in raising the 50-kg sack is _______ compared to the power expended raising the 25-kg sack
They are equal!
400
A 5 kg object is held 5 m above the ground. What is its gravitational potential energy?
250 J
400
A pendulum is swinging back and forth. As the pendulum moves from its lowest point to its highest point, its energy transfers from Kinetic Energy to this type of energy.
Potential energy
400
The equation ∆PE = ∆KE shows how energy may be converted. In the same equation ∆mgh = ∆1/2*m*v^2, the _______ of the object cancels out in PE and KE.
Mass! This means that the mass of the object does not matter when finding out how much energy is transferred from PE to KE or KE to PE.
500
A clerk can lift containers a vertical distance of 1 meter or can roll them up a 2 meter-long ramp to the same elevation. With the ramp, the applied force required is about _________ the original force
One half of
500
A 50 kg box is pushed a distance of 10 m across the floor with a 5 N force in a time of 2 seconds. How much power is expended?
25 watts
500
Why is potential energy called POTENTIAL energy?
Potential energy is stored energy. An object with PE has the POTENTIAL to do work.
500
Two cars of the same mass are speeding, one with twice the velocity of the other. When they slam on their brakes, how does the stopping distance of the faster car compare to the slower car?
The faster car stops in a distance 4 times that of the slower car.
500
When there is friction present (a non-conservative force), where does the energy go when it is "lost"?
It is transformed into heat/thermal energy