Show:
Work
Power
Energy
Conservation of Energy
Miscellaneous
100

When you push a door that says "pull"... is work being done on the door? Include your reasoning. 

No, because the door is not displaced

100

Power is the rate of transfer of ______. 

Energy 

100

Which type of energy only exists as a property of a system and is associated with the objects' position, orientation, and configuration?

Potential Energy

100

A ball is thrown horizontally (like a horizontal projectile) off the top of MHS. In that instant, what type of energy does the ball have?

Kinetic + gravitational potential energy

100

What do you draw for the L's in the LOL diagram? 

Energy bar graphs

200

True or False: Work is multiplying the perpendicular component of the force vector by the displacement vector, and therefore W = Fdsin(theta) 

False; we use the parallel component between the force and the displacement vectors. 


W = Fdcos(theta)
200

What are the two formulas for calculating average power?

P = W/t = Fv 

200

What is formula for spring potential energy? 

Us = (1/2)kx2

200
The roller coaster cart at the top of a 20 m tall track has a total mechanical energy of 3000 J. Assuming there is no friction or air resistance, what is its kinetic energy when the cart reaches the bottom of the track on the ground? 
3000 J
200

What are the two conservative forces we have learned thus far? 

Gravity & Spring Force

300

When a ball is falling, does air resistance do positive or negative work? 

Negative (the ball's displacement is downward while the air resistance force vector points upward)

300

What is the average power exerted by a man lifting a 500 N weight with a constant speed of 2 m/s? 

1000 Watts 

300

You and your friend want to get to the peak of a mountain. Your friend takes the ski lift while you take the long path by foot. Assuming that you and your friend have equal mass, compare your gravitational potential energy when you both reach the top. 

Both of you have the same amount of potential energy.

300

A ball has an initial potential energy of 300 J and an initial kinetic energy of 500 J. A few seconds later, its potential energy increased to 600 J. What is its kinetic energy at that point? Assume no dissipative forces. 

200 J. 

300

What is one property of Conservative forces that we have learned thus far? 

A conservative force is associated with a potential energy 

400

How do you find work from a Force vs Position graph? 

Find the area under the graph. 

400

A force produces power P by doing work W in a time t. What is the power a force that does 4 times as much work in 1/3 as much time will produce?

12P

400

If both the mass and the velocity of a ball are doubled, the kinetic energy is increased by a factor of ___?

8

400
A 3 kg ball is dropped from a 10 m tall building. Ignore air resistance. Halfway through the fall (at 5 m above ground), how much kinetic energy does it have? 

150 J 

400

The mechanical energy of the system is conserved unless _________________ does work on the system 

An external (net) force

500

What is the total work done on an object when it moves with a constant speed of 4 m/s through a distance of 10 m? 

Zero 
500

What is the average power exerted by a man lifting a 200 N weight up 8 meters in 4 seconds? 

400 Watts

500

A steel marble of mass m attached to the end of a spring causes it to stretch x cm. If another marble of mass 4m is added to the spring, the potential energy of the spring will be increased by a factor of _____. 

25

500
Mary slides down a frictionless, 20m-tall water slide at the water park. What is her velocity when she reaches the bottom of the slide? 

20 m/s

500

Only the _______ in potential energy has significance. This is also why we can redefine our "ground" or reference point when we solve conservation of energy problems. 

Change or Difference