Step-by-step solutionWe start by stating the law of conservation of energy in equation form, and then adapting it to fit the specifics of Sam’s trampoline jump.Now we have a simpler equation for Sam’s energy. The task now is to solve it for the one unknown variable, his speed at the surface of the
trampoline.Step Reason
1. Ef = Ei law of conservation of energy
2. KEf + PEf = KEi + PEi energy is mechanical energy
3. KEf + 0 = 0 + PEi enter values
4. KEf = PEi simplify
Step Reason
5. KEf = PEi state equation again
6. ½mv^2 = mgh definitions of KE, PE
7. solve for v
8. enter values
9. v = 2.2 m/s evaluate
6.18 - Interactive checkpoint: conservation of energy
A boy releases a pork chop on a
rope. The chop is moving at a speed
of 8.52 m/s at the bottom of its swing.
How much higher than this point is
the point from which the pork chop is
released? Assume that it has no initial
speed when starting its swing.
Answer:h= m
(^138) Copyright 2007 Kinetic Books Co. Chapter 06