What's a joule?
(Ex. 55 Joules or 55J)
What is unit of energy
For two objects with the same mass, the more ______, the more potential energy.
Height/altitude/distance from ground
What is the law of conservation of energy?
A. The energy of movement.
B. The energy stored in an object.
C. The idea that energy cannot be created or destroyed, only transformed.
D. The sum of kinetic and potential energy.
C. The idea that energy cannot be created or destroyed, only transformed.
A position where an object has no potential energy
On the ground
What is thermal energy?
energy of heat
A roller coaster is at the top of the track. What kind of energy does it have?
Gravitational Potential (just Potential is valid)
Kinetic Energy is affected by ___________ and ____________ of an object.
Mass and speed/velocity
Which of these has the most kinetic energy?
A. a 25kg fish tank sitting on a table
B. a 50g fish swimming in a fish tank
C. a 7,500kg car parked on a steep hill.
D. a boulder sitting on top of a cliff.
B. a 50g fish swimming in a fish tank
The kinetic energy of a ball at the bottom of a hill equals________.
What is potential energy at the top?
What kind of energy is a battery?
chemical potential energy
A ball is rolling at the bottom of a hill. What kind of energy does it have?
What is kinetic
What increases the total kinetic energy more? Doubling the mass or doubling the speed?
Doubling the speed has a greater effect on the kinetic energy because the speed term is squared in the equation.
KE = .5mv2
Which change would increase the kinetic energy of a moving object the most?
A. reducing the mass by half
B. reducing the speed by half
C. doubling the mass of the object
D. doubling the speed of the object
D. doubling the speed of the object
KE = 1/2 x mass x speed2
Speed term is squared so it'll have a greater effect on the kinetic energy than increasing mass.
This is a swinging pendulum. At which position will most of the pendulum's potential energy have been converted to kinetic?

A. Position 1
B. Position 2
C. Position 3
D. All positions have the same potential energy.
C. Position 3
Bottom of its path.. the potential it started with became kinetic as it moved!
What kind of energy does a diver have standing on a diving board?
gravitational potential energy
What type of energy is stored in food?
Chemical
What is the formula for potential energy?
PE = mass x gravity x height
PE = mgh
Which of these has correctly calculated the potential energy of a 2kg book sitting on top of a 2m book shelf? Gravity = 10 m/s2 and PE = mgh
A. 14 J
B. 4 J
C. 40 J
D. 20 J
C. 40 Joules of energy
This diagram shows a cart moving freely (no friction) along a track. Which best describes the energy transformations from point A to point B

A. Potential energy is transformed to kinetic energy.
B. Kinetic energy is transformed to potential energy.
C. Both potential energy and kinetic energy stay the same.
D. Potential energy decreases and kinetic energy stays the same.
A. Potential energy is transformed to kinetic energy.
Starts high up then MOVES down the track. losing height, gaining speed
What energy conversion is happening when you turn on the lights?
Electrical energy is converted into light (radiant or solar) energy.
What is the formula for kinetic energy?
KE = 1/2mv2
KE = .5 x mass x speed2
A person walking up the hill is transforming what kind of energy to what kind of energy?
kinetic energy to gravitational potential energy
How much kinetic energy does a 2kg bird have while flying 2m/s? KE = .5mv2
A. 8 J
B. 4 J
C. 6 J
D. 16 J
B. 4 Joules of energy
I have just launched a ball of clay into the air. I calculated its kinetic energy to be 10 J. Then I tore it in half and to make a ball that has half the mass. I launched the smaller ball into the air at the same speed. What is the kinetic energy of the smaller ball?
A. 10 J
B. 5 J
C. 9 J
D. 20 J
B. 5 J
Less massive, definitely cannot have the same or more energy. The speed didn't change. Think about the formula: if I put half the mass in, I get half the kinetic energy in return.
What energy conversion is happening when a bouncy ball hits the floor?
Kinetic energy is converted to thermal/sound