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let's assume that a car engine provides a constant amount of power. The car accelerates from zero to 30 m/s.

2006-12-17 17:39:13 · 8 answers · asked by Anonymous in Science & Mathematics Physics

8 answers

in order to determine whether acceleration is constant, you still missing one more information, the time.... how long did it take for the car to accelerate from zero to 30m/s

2006-12-18 00:49:36 · answer #1 · answered by katam 2 · 0 0

The power is constant, and let us assume all the energy gets converted to the kinetic energy of the car.

Power is the rate at which energy is produced, so constant power means the energy produced per unit time is constant.

By our assumption, the change in kinetic energy of the car per unit time is constant.

Since KE = (1/2) mv^2
>>
d(KE)/dt = constant

>>
2v .dv/dt = constant.

dv/dt is acceleration, so we get

velocity x acceleration = constant.

The higher the velocity, the smaller the acceleration, it keeps decreasing! (But never becomes 0).

2006-12-17 18:43:08 · answer #2 · answered by Seshagiri 3 · 0 0

Car Enginer = constand power.
Zero to 30m/s.

In real world sense, acceleration will not be constant due to wind directions, fuel quality(sendiments/ron), and road quality and type of tyres.

In physics/paper world, Car's acceleration is constant.

2006-12-17 17:50:31 · answer #3 · answered by mark k 3 · 0 0

No, the acceleration in the starting engine is higher than after.

2006-12-17 18:13:17 · answer #4 · answered by Anonymous · 0 0

Another way to look at this if you do not do calculus...

Power is force x velocity. This is easy to see because energy is force x distance, and power is energy / time -> force x distance / time.

Now if power is constant and velocity is increasing, then force MUST be decreasing. And force is proportional to acceleration.

So acceleration is decreasing.

2006-12-17 19:39:36 · answer #5 · answered by Anonymous · 0 0

surely the acceleration is constant

2006-12-17 17:42:58 · answer #6 · answered by James Chan 4 · 0 0

No, because friction and drag are not linear. Drag is a square law and would be significant enough to have an effect at 30m/s.

2006-12-17 17:52:12 · answer #7 · answered by Chris H 6 · 0 0

As long as you got your foot on the gas

2006-12-17 17:47:06 · answer #8 · answered by Chris B 4 · 0 0

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