If a car can accelerate at a rate of 15 m/hr/sec how long will it take the car to get to 65 m/hr
from a dead stop?
Let's start by converting everything to SI units.
15 m/hr/s = 6.71 m/s/s
65 m/hr = 29.1 m/s
We have constant acceleration, so we can use our constant acceleration kinematic formulas. Here we initial velocity, final velocity, acceleration, and want time so we use v(f) = v(i) + a[t(f) - t(i)].
We assume t(i) = 0, so our equation becomes
29.1 = 0 + 6.71[t(f)]
t(f) = 4.34 sec