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My wife is taking a Physics class and is having some trouble. I've never taken physics but I've tried to help, with no luck.

What net external force is required to accelerate a 1500kg car from rest to 100km/h in 10 seconds?

She believes that the right equation is:

F=ma

100km/1hour x 1hour/60sec = 100/60 = 1.7km/s

a=(1.7 km/s)/10s

a=0.17s/km

F=1500kg x 0.17s

F=255

-------------------------------

So we got '255N'

The book says the answer is '4167N'

But it does not say how to get this.

She is studying for a test tomorrow.

Any help would be great.

Thanks

**1. Homework Statement**What net external force is required to accelerate a 1500kg car from rest to 100km/h in 10 seconds?

**2. Homework Equations**She believes that the right equation is:

F=ma

**3. The Attempt at a Solution**100km/1hour x 1hour/60sec = 100/60 = 1.7km/s

a=(1.7 km/s)/10s

a=0.17s/km

F=1500kg x 0.17s

F=255

-------------------------------

So we got '255N'

The book says the answer is '4167N'

But it does not say how to get this.

She is studying for a test tomorrow.

Any help would be great.

Thanks

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