A car was stopped at a red light. When the light turns green, the car reaches a speed of 41 miles per hour in 2 seconds. What is the acceleration, to 1 decimal place?

Answer 1

s(t) = (a/2)t^2 + vot = so, vo= initial velocity = 0, so = initial distance = 0

s(t) =at^2/2

velocity = the derivative of the distance function

v(t) = at

v(2) = 41 = a(2) = 2a

a = 41/2 = 20.5 miles per second per second

a = 20 1/2 m./sec^2