Definitions
What is mass?
The amount of space an object takes up. (Basically its weight, but regardless of gravity
What is the formula for calculating PE?
PE = m x g x h
Which has more Kinetic Energy, a ball moving at 3 m/s or 5 m/s?
5 m/s
In calculating PE, and KE energy problems, what unit is used for height?
Meters
What is Energy?
The ability to do work.
What is Velocity?
How fast an object is traveling.
Calculate the PE of a rock that has a mass of 60 kg and is 10 m high.
5886 J
mgh
Determine the kinetic energy in a 7 kg ball thrown with a velocity of 21 m/s.
1543.5 J
1/2mv^2
In calculating PE and KE problems, what unit is mass?
Kilogram
Why do you come back down when you jump into the air?
Gravity!
What is the difference between kinetic energy and potential energy?
Kinetic energy is motion. Potential energy is stored energy due to it's position (height).
How much potential energy would a 3 kg table have if it's at the top of a hill 117 m high?
3443.31 J
mgh
The computer weighs 3 kg and is thrown at a velocity of 5 m/s. Calculate the Kinetic energy.
37.5 J
1/2mv^2
In calculating KE and PE problems, what unit is velocity?
m/s
List 3 forms of potential energy
Gravitational, elastic, chemical, mechanical
What is gravity?
The force that pulls us towards the ground. 9.8 m/s2
Which has more potential energy, a calculator on the ground or a calculator on the table 1.5 m high?
on the table. (greater height)
Calculate the kinetic energy of a 15 kg cart going 60 m/s.
27000 J
1/2mv^2
What is the unit for Kinetic Energy?
Joules (or Newton meter)
List some forms of kinetic energy.
Motion (mechanical), heat (thermal), sound, light (radiant), electrical
What is height and how is it measured scientifically?
How high, or tall something is, measured in meters.
Why might there be more Potential Energy at the top of a roller coaster than at the end of the ride?
Potential Energy decreases as Kinetic Energy Increases.
Lt Col Tryon's pencil weighs 0.05 kg and is dropped from the table 1 m high. The pencil falls at a velocity of 9.8 m/s. What is the pencil's KE?
.49 J
1/2mv^2 = mgh
(2)(9.81) = v^2
v = 4.429
or just take the PE to solve for KE
What unit is used for Potential Energy?
Joules (or Newton Meter)
What is the law of conservation of energy?
Energy cannot be created nor destroyed, only changed in form.