this is the question

Suppose that a car can accelerate from 30 mph to 50 mph in 4 seconds. Assuming a constant acceleration, find the acceleration (in miles per second squared) of the car and find the distance traveled by the car during the 4 seconds.

the

*FIND* of the problem is "distance" traveled.

*Given* of the problem is:

Initial velocity = 30 mph = u

final velocity = 50 mph = v

elapsed time = 4 sec = 1/900 hour = t

Assume linear motion and constant acceleration - then we can use Galileo's equations (a = acceleration and s = distance traveled)- which are:

v = u + a*t............................(1)

s = u*t + (1/2) * a * t^2.........(2)

v^2 = u^2 + 2 * a * s ...........(3)

Looking at these equations (and other givens) - we formulate our strategy:

using equation (1) we get,

a = (v - u)/t = 18000 mph^2 ....................(be very cognizant about the

*units* in these problems)

then we use equation (3), to get,

s = (v^2 - u^2)/(2*a) ................................complete it using the given and the calculated data. Be careful about the

*unit* of 's'.

and the FIND is found!