Complete the Missing information

PE = 1200 J

KE = 0 J

PE = ______ J

KE = 400 J

PE = 300 J

KE = _______ J

PE = 0 J

KE = ________ J

Energy Conversion Energy Conversion CalculationsCalculationsSection 15.2Pages 457-458

Energy Conversion CalculationsEnergy Conversion Calculations Mechanical energy is the total amount of

kinetic and potential energy.

Because of the law of conservation of

energy, total mechanical energy remains

constant if there are no external forces.

TMEbeginning = TMEend

(KE + PE)beginning = (KE + PE)end

Reminder: KE=1/2mv2

GPE=mgh

Example #1Example #1A diver with a mass of 70 kg stands motionless at the top of a 3.0 m high diving platform, Calculate his potential energy relative to the water surface while standing on the platform, and his speed when he enters to pool. (Assume the diver’s initial vertical speed after

diving is zero.)

Example #2

A 1.25 kg stone fell from a cliff and struck the ground at a speed of 29.4 m/s. How high was the stone before it fell?