Units Units Units
The units for distance or height.
meters (m)?
W
work
This is energy of motion.
kinetic energy
This law states that energy can neither be created, nor destroyed, but only change forms.
Law of Conservation of Energy
This uses energy and can create energy. It is calculated by multiplying force times distance.
work
The unit for velocity.
meters per second (m/s)?
KE
kinetic energy
This is energy of position, in relation to the Earth.
gravitational potential energy
The potential energy of a roller coaster at the top of a hill is equal to this at the bottom of the hill.
Its kinetic energy
This is the rate at which work is done.
power
The unit for energy or work.
joules (J)?
The formula for calculating work.
W=Fd cos theta
A roller coaster at the top of the first hill has only this type of energy.
gravitational potential energy
A baseball is thrown straight up into the air with 50 J of kinetic energy. This is the amount of potential energy it has at the top of its trajectory.
50 J
This is the amount of work done on a heavy bag hanging from your shoulder.
none (0 J)
The units for force.
newtons (N)
The formula for calculating power.
P=W/t
A baseball that has been thrown straight up in the air has only this type of energy at the moment it has first been thrown.
kinetic energy
A stone is dropped from a height of 200 m above the ground. At this height in its fall, the kinetic energy is equal to the potential energy (assuming that it has zero potential energy at ground level).
100 m (halfway)
Zola pushes a 15 kg wheelbarrow by exerting a force of 125 N, moving it 50.0 m. This is the work done by Zola.
6,250 J
The units for power.
Watts (w)
The formula for calculating potential energy.
PE=mgh
At this point in the fall of a projectile, it has equal amounts of potential and kinetic energy.
halfway
A 5-kg brick falls to the ground from a 4-m-high roof. This is the kinetic energy of the brick just before it touches the ground.
196 J
The kinetic energy of a car is 10,000,000 J as it travels along a horizontal road. This is how much power is required to stop the car in 5 s.
2,000,000 W