# Homework Help: Acceleration of cars

1. Apr 16, 2010

### DV10

1. The problem statement, all variables and given/known data

How do cars accelerate?

2. Relevant equations

f=ma

3. The attempt at a solution
the only external force on a car is friction,generally forward directioned for the back wheels n backward directioned for the front ones.when a car accelerates how is this friction varied?
i mean for a given dimension n wieght,will not the maximum acceleration be same for all cars irrespective of their engines?(because max friction is (myu)*(Normal reaction) where myu is coefficient of friction)

2. Apr 16, 2010

### PhanthomJay

looking in the horizontal direction , and neglecting air drag, this is correct, except that friction acts forward on the driving wheels, and backwards on the non driving wheels
Provided that the smaller powered car has enough horsepower to deliver the required maximum friction force, this would be correct (in absence of other variables). So if you had a low power car and a high power car, of the same mass, and they were accelerating from rest on a icy (low friction coefficient) surface, wheels not sliding, how would their accelerations compare in this case, and how would they differ if they both instead were on a dry surface?