3.2 Conservation
Roller Coasters
Test your knowledge by trying the problems below.
Always start your calculation problems with: Ebefore = Eafter
Example #1:
A roller coaster uses 1 000 000 J of energy (Work in) to get to the top of the first hill. During this climb, it gains 400 000 J of potential energy and pauses (velocity = 0) for a fraction of a second at the very top before heading down the other side.
a) What's the kinetic energy at the very top?
b) What would be the "useful energy" during it's climb to the top?
c) How much energy was lost due to friction? (Use Ebefore = Eafter).
d) Calculate the efficiency of the roller coaster during this part of the ride (the climb).
Try before checking solution.
Example #2:
The same roller coaster goes over the top of the first hill and heads downwards. The roller coaster heads down and levels out as it hits the original level.
a) Since they are back at the original level, what do we know about the potential energy at this point?
b) If we assumed that there is no loss due to friction, what would be the kinetic energy at the bottom? (Use Ebefore = Eafter)
c) The actual kinetic energy at the bottom turned out to be 240 000J, what is the efficiency of the roller coaster during this part of the ride?
d) Where would the wasted energy have gone?
Try before checking solution.
