Section+4.3+-+Gravitational+Potential+Energy+at+Earth's+Surface



**__ 4.3 Gravitational Potential Energy at the Earth’s Surface __** · Gravitational potential energy is due to an object’s elevation relative to the earth’s surface.

Ex. Roller Coasters

When a roller coaster is at the top of its highest hill it is said to have it’s highest amount of gravitational potential energy relative the surface of the earth

· The Formula for Gravitational Potential Energy (derivation): W = (F Cos ∂) ∆y W = mg (Cos 0˚) ∆y W = mg∆y ∆Eg = mg∆y

· Notice that this formula is dependant on mass and height!

· Variables in this Formula and Units:

o ∆Eg § Change in gravitational potential energy § Measured in Joules (J) o m  § Mass of the object § Measured in kilograms (kg) o g  § Acceleration due to gravity § Measured in metres per second squared m/s2 § On the earth this value is 9.80m/s2 o ∆y § Vertical component of displacement § Measured in metres (m)

APPLICATION OF CONCEPTS · Maximum gravitational potential energy of a system will mean 0 kinetic energy · When a system has maximum kinetic energy it will have 0 gravitational potential energy