Question

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.

Part A What is the maximum acceleration of the Porsche on a concrete surface where μs=1.00? Express your answer with the appropriate units. View Available Hint(s) amaxa m a x = nothing nothing

Part B If the Porsche accelerates at amax, what is its speed when it reaches maximum power output?

Answer 1

Answer:

a = 6.53 m/s^2

v = 11.5689 m/s

Explanation:

Given data:

engine power is 217 hp

70 % power reached to wheel

total mass ( car + driver) is 1530 kg

from the data given

2/3 rd of weight is over the wheel

w = 2/3rd mg

maximum force

$F = \mu W$

we know that F = ma

$ma =  \mu (2/3 mg)$

$a_{max} = 2/3(1.00) (9.8) = 6.53 m/s^2$

the new power is $p  = 70\% P_[max} = 0.7 P_{max}$

$P =f_{max} v$

$0.7P_{max} = ma_{max} v$

solving for speed v

$v =0.7 \times \frac{P_{max}}{ma_{max}}$

$v = 0.7 \frac{217 [\frac{746 w}{1 hp}]}{1500 \times 6.53}$

v = 11.5689 m/s