Gravitational Potential Energy on Earth

1. Gravitational Potential Energy on Earth • Recall that on a planet (or moon, etc.) gravitational potential energy can be found using the following: Eg = gravitational potential energy (J) m = mass of object (kg) h = height of object above reference point (m) g = gravitational field strength (N/kg) = 9.8 N/kg on Earth

2. 1. Determine the gravitational potential energy of a 240 kg emu relative to Iggy's deck when the bird is a) perched on the railing 2.2 m above the deck. b) standing on the ground 1.9 m below the deck.

3. Conservation of Energy on Earth • In any transfer of energy between systems, the total energy before the transfer equals the total energy after. • Energy can neither be created nor destroyed (it just changes forms)

4. ET = total mechanical energy before transfer (J) E'T = total mechanical energy after transfer (J) OR ... 2. James Howlett is fired from a cannon atop a 23 m high cliff at a speed of 17 m/s. What is his speed when he hits the water below? (ignore air resistance) Dissipated (wasted) energy

5. 2. What would Howlett's impact speed be if 10400 J of energy were dissipated due to air resistance? His mass is 80 kg.