- #1
goli12
- 11
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Homework Statement
Hey guys I have two questions. The first one I'm not sure, while the second one, I have some idea but don't know how to proceed with answering the question.
1. A rapidly spinning flywheel has been suggested as an energy storage mechanism for cars. Let's consider a 300kg uniform disk flywheel of diameter of 0.5m spinning at 100 rotations per second. Find the energy stored in the spinning flywheel. How higha hill could the 1000kg car (including the flywheel) climb with this energy?
2. Calculate the force on a 1kg chunk of metal near the edge of the disk.
Homework Equations
ω=2∏/T
Erot=0.5Iω2=0.25MR2ω2
Erot=Ep
The Attempt at a Solution
1.
ω=2∏*100/1=628rads-1
The total mass of the car is 1000kg which includes the flywheels. In total there are 4 flywheels on the car. So the mass of the car is distributed among the 4 wheels.
M=1000/4=250kg (per wheel)
Using the third equation,
Erot=0.25*250*0.252*6282=1540562.5J
This is the energy for one wheel. Therefore, the total energy of the 4 wheel is 4*1540562.5=6162250J.
Using conservation of energy (last equation) 6162250=250*9.8*h.
Solving for h: h=6162250/(250*9.8)=2515m
2.
For this question, I know that I have to find the tangential force, but, how would i start? Is the tangential force a component of centripetal force?
Many thanks :D