<p>PHYSICS LECTURE W & E – 3: POTENTIAL ENERGY & TMC</p><p>POTENTIAL ENERGY . Stored Energy . Associated with an object that has the potential to move because of its position relative to some other location . ______. SI unit for potential energy is a Joule (J) which is equivalent to newtons times meters (N·m).</p><p>GRAVITATIONAL POTENTIAL ENERGY . The energy associated with an object due the object’s position relative to some gravitational source . Depends on both the height and the free-fall acceleration . It must be measured relative to some zero level. . FORMULA: gravitational potential energy = mass x free-fall acceleration x height</p><p>______</p><p>ELASTIC POTENTIAL ENERGY . The energy stored in any stretched or compressed object . Depends on the distance the object is compressed or stretched from its relaxed length . The spring constant (k) is a measure of a spring’s resistance to being compressed or stretched. o ______o ______o ______. FORMULA: o elastic potential energy = ½ x spring constant x (distance compressed or stretch)2</p><p> o ______</p><p>POTENTIAL ENERGY EXAMPLE PROBLEM: A 70.0 kg stuntman is attached to a bungee cord with an unstretched length of 15.0 m. He jumps off a bridge spanning a river from a height of 50.0 m. When he finally stops, the cord has a stretched length of 44.0 m. Assuming the spring constant of the bungee cord is 71.8 N/m, what is the total potential energy relative to the water when the man stops falling? G:</p><p>U:</p><p>E:</p><p>S:</p><p>S:</p><p>1 PHYSICS LECTURE W & E – 3: POTENTIAL ENERGY & TMC</p><p>CONSERVATION OF MECHANICAL ENERGY</p><p>. Mechanical energy is the sum of kinetic energy and all forms of potential energy</p><p> o ______</p><p>. In the absence of friction, Mechanical Energy is conserved.</p><p> o ______</p><p> o ______</p><p>. Conservation of Mechanical Energy Principle o Initial mechanical energy = final mechanical energy (in the absence of friction)</p><p> o ______</p><p> o ______</p><p>CONSERVATION OF MECHANICAL ENERGY EXAMPLE PROBLEM:</p><p>Starting from rest, a child with a mass of 25.0 kg zooms down a frictionless slide from an initial height of 3.00 m. What is her speed at the bottom of the slide? </p><p>G:</p><p>U:</p><p>E:</p><p>S:</p><p>S: 2</p>