Show:
Work
Kinetic Energy
Potential Gravitational and Elastic Energy
Conservation of Mechanical Energy
Power
100
Work is a scalar quantity, true or false?
True
100
Increasing the kinetic energy of a moving object of 10kg will increase it's what?
Velocity
100
If the potential gravitational energy of a 10kg object changes, it's what will change?
Height/ position
100
True or False, if no energy leaves the system, energy remains perfectly conserved
True
100
Power is Work over the change in what?
Time
200
Work is a negative quantity when force is in what direction relative to displacement?
The opposite direction. 180 degrees
200
If the velocity of an object gets doubled, its kinetic energy will be increased by a factor of what?
4/ quadrupled
200
The potential elastic energy of an object changes. Name 2 things that could get changed.
K constant and compression/ stretch amount.
200
The idea of the conservation of mechanical energy is possible because we can set work equal to what?
The change in energy (kinetic being the case we've worked with the most)
200
Using a tow truck to take a car up a hill is more effective than pushing a car up a hill because the truck can exert more what?
Power
300
Is work measured in the same units as energy?
Yes, work is also measured in joules. Providing work provides energy to a system.
300
The CHANGE in kinetic energy is equal to what?
Work
300
Doubling the vertical position of a 10kg object will change its potential gravitational energy by a factor of what?
2 / double
300
A person jumps on a trampoline and is sprung 3m into the air. On the person's return trip, at some point of time is at 2m above the surface of the trampoline. Look at this point of time and tell me initial and final energies are being looked at. Answer in the form of: The initial energy/energies are.... and the final energy/energies are...
The initial energy is potential elastic here, and the final energies are potential gravitational and kinetic energies
300

How much energy does a 100W light bulb use in a minute

6,000J

400
There's a force of 500N that is constantly exerted upward on a crate of books that was carried 10 meters to the left. How much work is done?
0 because Force and displacement are perpendicular in this situation
400
An 800kg car gets slowed down from 30 m/s to 10 m/s. How much work was done to the car?
800*(30m/s - 10 m/s) = 800*20 m/s = 16,000 J
400
True or false, springs are the only objects allowed to possess potential elastic energy.
False
400
List at least 2 examples of what happens when energy is not perfectly conserved in a system.
An object doesn't return to its initial height, an object slows down over time; an object doesn't compress or stretch to the same amount over time... etc.
400
A horse does 50,000J of work in 20 seconds while a small go kart does 1,000J of work in 1 second. Which one has exerted more power?
The horse, horse's power = 2,500W here, go kart's = 1,000W
500

Explain if work is a scalar or vector quantity and why

Scalar quantity because the cosine from the dot product tells us the relationship between force and displacement in a scenario. It can't tell us what direction that force and displacement are moving in time though.

500

After a hockey player hits a 0.5kg puck to the right. It is traveling at 15 m/s on ice that has a coefficient of kinetic friction of 0.1. It comes to a stop 20m away. If left is positive, using what you know about kinetic energy, tell me what sign work is.

Negative because force opposes displacement here since the force here is friction.

500
Explain the difference between the h in potential gravitational, the x in potential elastic, and the d in work.
h is for height of an object, x is the amount of stretch or compression of an object, and d is the displacement of an object by a force
500
List at least 3 variables that could be looked at when it seems that energy is not conserved in a system.
Heat, sound, air resistance, friction, rolling friction, electricity, magnetic energy, gravitational attraction, etc.
500
What is the difference between running up 20 stairs versus walking up 20 stairs?
The amount of power that is exerted