Question

A sports car claims that it can start from rest and reach 60mph (26.8 m/s) in a distance of 33.5 meters. To reach its maximummspeed, it accelerates at this constant rate for 11.25seconds.

a) How many seconds does it take to reach 60 mph?
- I got 1.25 seconds

b) What is the maximum speed of this car?
- Using kinematics I got 120.6 m/s

c) If the mass is 1900 kg, what force must the car provide tokeep it traveling at this maximum speed ( Hint: don't forgetfriction)

- I know that Fnet= mass x acceleration, and that gives me1900 x 10.72 = 20,368 N

but this is not taking into account friction. What role doesfriction play and how can I calculate it properly?

d) I was driving this car at a maximum speed on a test trackwhen a deer ran out in front of me. My reaction time was 0.5seconds, before I hit the brakes. Assuming that the engine is nolonger applying any forward force, and my wheels lock up, how farwill I travel before I come to a stop after seeing the deer (giveanswer in miles, using: 1 Km = 0.62 miles)?

e) How much time will elapse from the time that I see the deeruntil I stop?