Question | Answer |
P3h - The energy of games and theme rides | . |
Gravitational Potential Energy (GPE) | An object held above the ground has Gravitational Potential Energy. The amount of GPE an object on Earth has depends on its: Mass and Height above the ground. |
Continue... | If an object is lifted, work is done against gravitational force. GPE = mgh or GPE = m × g × h GPE = the gravitational potential energy in joules, J m = the mass in kilograms, kg g = the gravitational field strength in newtons per kilogram, N/kg h = the change in height in metres, m |
Energy Transfers | A bouncing ball converts GPE to Kinetic Energy and back to GPE. It doesn't return to it's original height because energy is transferred. |
Kinetic Energy | KE = ½ mv2 |
Energy Transfer | When an object falls through the atmosphere at terminal speed: its kinetic energy, KE, does not increase gravitational potential energy, GPE is transferred to the surroundings as heat because of friction (air resistance). |
How roller-coasters work | The riders at the top of a roller coaster ride have a lot of gravitational potential energy. When the train is released, it converts GPE to kinetic energy as it falls. This is shown in the formula: loss in GPE = gain in KE |
Continue... | As the train falls: GPE = KE … so … mgh = ½ mv2 Notice that m appears on both sides of the equation and can be cancelled out: gh = ½ v2 This equation can be rearranged to give: h = v2 ÷ 2g |
The kinetic energy an object has depends on its: Mass – if the mass doubles, the KE doubles Speed – if the speed doubles, the KE quadruples (increases four times). | . |
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