if car 2 came to a stop in 15 seconds how much power in (watts) did it take to stop car 2 at the stop sign by applying force to the brakes?
Can someone PLEASE show me how to figure this problem out. Help would be greatly apperciated.
2006-11-27 10:03:30 · 4 answers · asked by Lizzie 5 in Science & Mathematics ➔ Physics
Power is the rate at which work is done. It is the work/time ratio.
Work = force * distance
What force was used to stop the car?
What distance did it travel?
2006-11-27 10:06:54 · answer #1 · answered by DanE 7 · 0⤊ 0⤋
A car has some velocity before it begins to stop. And the mass of the car matters.
Let the mass be M, and the initial velocity be V.
Then its kinetic energy is
Ek = MV^2/2.
When we are applying force to the brakes, some energy goes to overcome friction, and this energy goes from kinetic energy.
So, assuming that we apply equal force to the brakes during these 15 seconds, and the energy consumption also is equal in time. And all the kinetik energy Ek will be spent during these 15 seconds to/by brakes friction.
The power of the energy consumption is then Ek divided by 15 seconds:
W = Ek/T = Ek(J)/15sec
So, please check that the mass be in kg, and the velocity in m/sec, then you will receive Ek in J, and dividing it by sec, you will receive the final result in W
2006-11-27 18:36:05 · answer #2 · answered by Oakes 2 · 0⤊ 0⤋
You are going to have to have the mass of the car. Obviously a Volkswagon will take less power than a Cadillac,
2006-11-27 18:06:33 · answer #3 · answered by Anonymous · 0⤊ 1⤋
need to know the mass and velocity of the car
2006-11-27 18:06:33 · answer #4 · answered by SteveA8 6 · 0⤊ 1⤋