Energy!
Energy is the ability ___________________
to do work
How much work is done on a sled that is pushed with 20N of force for 1.25 meters?
25 J
What is a closed system
One that accounts for everything in the system. There are no external forces.
Potential and kinetic energy are _____ proportional
inversely
The higher up something is from earth, the more _________ __________ _________ it has.
gravitational potential energy
If it takes 40 J of work to pull a wagon 5m, how much force are you pulling with? (assume no friction)
8 N
What does the law of conservation of energy state?
In any closed system, the total amount of energy must remain constant.
When velocity increases, kinetic energy _______
increases
A 0.5kg ball is held 1.5m above the ground. What is its potential energy?
7.35 J
If it takes 35J of work to lift a bucket into a treehouse with a pully, over the course of 6.5 seconds, how much power was expended?
5.38 W
Give an example of an elastic collision
answers will vary
The dinning hall is 70m from your dorm room. If you walk to the dining hall and back (to your dorm room), what is your displacement?
0 m
How much kinetic energy is in a 0.02kg hockey puck sliding at 20 m/s?
4 J
50N of force is used to push an object 2m. If this process takes 4 seconds, how much power was expended?
25 W
Give an example of an inelastic collision
Answers will vary
Is the following an elastic or inelastic collision:
A cue hitting a pool ball
Elastic
A 0.02kg hockey puck has 3.5J of energy. How fast is it moving?
18.7 J
A certain lightbulb is labeled to be 80W. How much work would it take to run the lightbulb for a minute?
P=W/t
80=W/60
4,800 J
The _______________ says "In the absence of an external force, the momentum of a system remains unchanged"
The law of conservation of momentum
Rearrange the kinetic energy equation to solve for velocity. Leave your final answer in terms of variables (you do not need to plug in numbers)
v = sqrt (2 KE/ m)