A car accelerates uniformly from rest and

Question

reaches a speed of 29.1 m/s in 6.5 s. The
diameter of a tire is 83.4 cm.
Find the number of revolutions the tire
makes during this motion, assuming no slipping.
Answer in units of rev

Answer 1

a = 29.1/6.5 = 4.48 m/s^2
average speed = 29.1/2 = 14.55 m/s
d =average speed * time = 14.55 * 6.5 = 94.6 meters

circumference of tire = pi D = 3.14 * 0.834 = 2.62 meters
so
94.6 / 2.62 turns

Answer 2

V = Vo + a*T.
29.1 = 0 + a*6.5,
a = 4.48 m/s^2.

d = 0.5*a*T^2 = 0.5*4.48*6.5^2 = 94.6 m.

C = pi*2r = 3.14*0.834 = 2.62 m. = Circumference.

Rev. = 94.6/2.62 = 36.1.