A Lamborghini sports car can accelerate from zero to 60 mph in 4 seconds. It can decelerate from 60 mph to rest in 120 ft. What is the ratio of average acceleration over average deceleration? (1 mile = 5280 ft).
I know the answer is .682, but I'm not sure how to get to that.
2 answers
How do you know the answer is .682 if you can't get there.
V = 60mi/h * 1600m/mi * 1h/3600s = 26.7 m/s.
V = Vo + a*t = 26.7.
0 + a*4 = 26.7
a = 6.67 m/s^2.
d = 120Ft/(3.3ft/m) = 36.4 m.
V^2 = Vo^2 + 2a*d = 0.
(26.7)^2 + 2a*36.4 = 0
a = -9.79 m/s^2.
deceleration = 9.79 m/s^2.
Ratio = 6.67/9.79 = 0.681.
V = Vo + a*t = 26.7.
0 + a*4 = 26.7
a = 6.67 m/s^2.
d = 120Ft/(3.3ft/m) = 36.4 m.
V^2 = Vo^2 + 2a*d = 0.
(26.7)^2 + 2a*36.4 = 0
a = -9.79 m/s^2.
deceleration = 9.79 m/s^2.
Ratio = 6.67/9.79 = 0.681.
2 answers