# Porsche's max speed

1. Mar 24, 2009

### tomboi03

A Porsche 944 Turbo has a rated engine power of 217 hp. 30% of the power is lost in the drive train, and 70% reaches the wheels. The total mass of the car and driver is 1530 kg, and two-thirds of the weight is over the drive wheels.

okay... sooo....

I know that P = F(car)*velocity = m*g*v+1/4*A*v^3
where A is the cross-section area.
But this problem doesn't have a cross-section area given.

Since the maximum power output is 217 hp and 70% of the power reaches the drive wheels.
P= (217hp)(0.70) = 151.9 hp

151.9hp * 746W/hp = 113317.4 W
and i don't know where to go with this.

2. Mar 24, 2009

### sArGe99

113317.4 W reaches the wheels.The total weight of the wheels = 2/3 * 1530 * 9.8

3. Mar 24, 2009

### tomboi03

okay uh... the thing is...

I know P=F*v right?
so, if P= 113317.4
and F= 9996

i get v= 11.336 m/s...
and that is not nearly enough for a porsche to reach it's max speed.... it's like the min speed if anything.

4. Mar 24, 2009

### tomboi03

nvm i got it! hahaha ;) thanks!