Skate Energy

Work

The product of force and displacement.

$W o r k = F o r c e * D i s t a n c e$

Figure: The work a skateboarder exerts is the product of the force used to propel the rider and the distance the rider travels.

A diagram showing that force times distance equals work.

Energy

The ability to do work.

Kinetic (KE)

The energy an object has due to it's motion.

K E = \frac{1}{2} * m a s s * v e l o c i t y^{2}

Mechanical
Thermal
Sound
Electrical

Potential (PE)

The energy an object has due to its position relative to other objects.

P E = m a s s * g r a v i t y * h e i g h t

Chemical
Nuclear
Gravitational
Electrical

Mechanical (ME)

The sum of kinetic and potential energy in an object.

Thermal (TE)

The energy that comes from friction and heat.

Energy Conversion

The total energy of an isolated system remains constant. This law means that energy can neither be created nor destroyed.

$E n e r g y_{i n i t i a l} = E n e r g y_{f i n a l}$

Figure: As the skateboard's position changes, its energy is transferred between potential and kinetic energy. The total amount of energy in the system at all four positions shown below is equal.

A diagram showing how much kinetic vs potential energy a skateboard uses during a halfpipe.

Power

The rate at which work is done or energy is transferred.

$P o w e r = \frac{W o r k}{T i m e}$

Since work is equal to force times distance,

$P o w e r = \frac{F o r c e \times D i s t a n c e}{T i m e}$

Velocity is equal to distance over time, thus,

$P o w e r = F o r c e X D i s t a n c e$

Energy Transfer

Energy cannot be created nor destroyed, but it can be transformed from one type to another, and from one system to another.

Figure: As the board travels down the ramp, its energy is transformed from potential energy to kinetic energy and thermal energy. The magnified view of the skateboard and ramp demonstrates that a small amount of thermal energy is transferred from the board to the ramp as it rolls along its surface.

A diagram showing the different types of energy a skateboard uses while going down a ramp.