What constant acceleration, in SI units, must a car have to go from zero to 60mph in 10 s? What fraction of g is this?
How far has the car traveled when it reaches 60 mph? Give your answer in SI units.
When the car reaches 60 mph, how far has it traveled ? Give your answer in feet.
Table of Contents
What is constant acceleration
v = at so a = v/t
t = 10 s
v = 60 mph = 26.82 ms^-1
a = (26.82 ms^-1) / (10 s) = 2.682 ms^-2
So the car is accelerating at 2.7 ms^-2.
And as distance = speed x time
distance = 26.82 ms^-1 x 10 s = 268.2 m
So the car has travelled 270 m in ten seconds.
Assuming that g = 9.8 ms^-2, then the fraction of g is a / g = (2.682 ms^-2) / (9.8 ms^-2) = 0.274.
That is, the car is accelerating at 27% of g.