Kinetic Events
Motion Energy
This energy is stored in fruit hanging in a tree.
Gravitational Potential Energy
What is the Law of Conservation of Energy?
Energy cannot be created or destroyed. It can only be transformed or transferred.
What is the equation for work?
Work = Force x Distance
What are the units of energy?
Joules (J)
What is the equation for Kinetic energy?
KE = 1/2 mv^2
A car's suspension system stores this type of energy
Elastic potential energy
At the bottom/lowest point on the track
What is the equation for Power?
Power = Work / Time
Elastic Potential Energy
If a 5 kg dog is running with a velocity of 3 m/s, what is the dog's kinetic energy?
KE = 22.5 J
A 7 kg cat jumps off the ground to a height of 0.75 m. What is the cat's GPE?
GPE = 51.45 J
A rock at the top of a hill has 100 J of GPE. How much KE will there be at the bottom? What is the total E?
What are the units of work? Power?
Work - J, Power - W
What variables does GPE depend on?
Mass, acceleration due to gravity, height
If the velocity of an object were to double, what would happen to the kinetic energy of the object?
It would quadruple (x4)
If your height decreases by half, what happens to your GPE?
It would decrease by half.
You pull back on a bow to fire an arrow. What energy transformation is occurring? (Assume no friction!)
EPE transforms to KE
If Mr. Chang pushes on a box with 15 N over a distance of 2 meters, how much work did he do?
W = 30 J
To calculate work, force and distance must be pointing . . .
In the same directionn
What variables does KE depend on?
A spring with a spring constant of 10 N/m stretches 1 meter. What is the EPE stored in the spring?
A pendulum is set swinging until it eventually comes to a stop. What energy transformations are occurring?
You push a chair with a force of 10 N over 2 meters in 5 seconds. How much power did you have?
P = 4 Watts
Always!