advanced/notes 6.6
TRANSCRIPT
Section 6.6Mechanical Energy and Its Conservation
Mechanical Energy and Its Conservation How do I solve problems utilizing conservation of mechanical energy?
Conservation If there are no nonconservative forces..
The sum of the changes in kinetic and potential energy is zero
Total Mechanical Energy (E) = KE + PE
Conservation means that E2 = E1 = constant
Conservation - Dropping a rock Total Mechanical Energy
Can calculate this for each stage of the rocks fall
Starts as all potential and changes to all kinetic
Conservation - Dropping a rock
Problem Solving
Set your y = 0
Be consistent with your subscripts
With a spring…
Example In the rock problem… If original height of the rock is 3.0 m, calculate the rocks speed when it has
fallen to 1.0 m above the ground.
Example If the height of the hill is 40 m, and the roller coaster starts from rest,
calculate (a) the speed of the roller coaster at the bottom of the hill, and (b) and at what height the speed will be ½ of (a). Use y = 0 at the bottom of the hill, and assume no friction.
Example Two water slides have the same
length and start at the same height. Both rides start from rest at the same time. (a) Which rider is traveling faster at the bottom? (b) Which rider makes it to the bottom first?
Homework Page 163 # 33 - 41
Power
Units are = Watts
Homework Worksheet