Acceleration/Velocity?

Question

A car accelerates from 0-62 mph in 3.7 seconds. How long would it take for it to reach 1/4 mile? Please explain.

Answer 1

vi=0

vf=62mph=62m/3600s

x=.25m

vf=vi+a*t

solve for a

x=vi*t+.5*a*t^2

solve for x

Answer 2

Your working formula is

S = VoT + (1/2)aT^2

where

S = distance travelled = 1/4 m = 0.25 mile

Vo = initial velocity = 0 (starts from rest)

a = acceleration

T = time required for car to travel 1/4 m.

To calculate acceleration "a",

a = (62 - 0)*(1/3600)(1/3.7)

a = 0.005 miles/sec^2

Therefore, substituting appropriate values in the above equation for "S",

0.25 = 0 + (1/2)(0.005)(T^2)

T^2 = 2 * .25/0.005

T^2 = 100

T = 10 sec.