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A car accelerates uniformly from rest and reaches a speed of 21.9 m/s in 8.99 s. Assume the diameter of a tire is 57.5 cm. (a) Find the numb
Question
A car accelerates uniformly from rest and reaches a speed of 21.9 m/s in 8.99 s. Assume the diameter of a tire is 57.5 cm. (a) Find the number of revolutions the tire makes during this motion, assuming that no slipping occurs.
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Physics
5 years
2021-08-29T09:40:12+00:00
2021-08-29T09:40:12+00:00 1 Answers
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Answer:
Explanation:
initial velocity, u = 0 m/s
time, t = 8.99 s
final velocity, v = 21.9 m/s
diameter of tyre, D = 57.5 cm
(a) Let a is the acceleration, and n be the number f revolutions made by the tyre.
Use first equation of motion
v = u + at
21.9 = 0 + a x 8.99
a = 2.44 m/s²
Use third equation of motion
v² = u² + 2 a s
21.9 x 21.9 = 0 + 2 x 2.44 x s
s = 98.28 m
Circumference of wheel, S = π x D = 3.14 x 0.575 = 1.8055 m
number of revolutions, n = distance / circumference
n = 98.28 / 1.8055
n = 54.4