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Work Done. Ashfield Direct Learning. Ks4 Energy. Lindzi Meek. Weight. Weight is due to the force of gravity. Every 1kg of matter has a weight of 10N near the surface of the earth due to gravity.
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Work Done Ashfield Direct Learning Ks4 Energy Lindzi Meek
Weight • Weight is due to the force of gravity. • Every 1kg of matter has a weight of 10N near the surface of the earth due to gravity. • The weight of objects near to the surface of the earth are numerically 10 times bigger than its mass in kg.
Gravitational Potential Energy • An object has gravitational potential energy if it has energy stored because it is at a height. • If an object can fall it has got Gravitational Potential Energy – GPE.
Example 1 • A skier who weighs 800N takes the ski lift which takes him from a height of 1000m to a height of 3000m above the ground. By how much does his gravitational potential energy change? E = mg × h = 800N × (3000m 1000m) = 800N × 2000m =1600000J • As the skier has gone UP it is an INCREASE in GPE
Example 2 • A crane lowers a load of 25000N from a height of 15m down to the ground. By how much does the gravitational potential energy of the load change? E = mg × h = 25000N × (15m-0m) = 25000N × 15m = 375000J • As the load has gone down • It is a DECREASE in GPE.