The wheels on a bicycle are 11.9 cm in diameter. The bicycle starts from rest and attains a velocity of 32 km/hr in 6.8 seconds. How many revolutions did the back wheel make during the 6.8 seconds?
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Assuming a constant acceleration you can use the average velocity to determine the distance covered but first you must get the velocity in m/s:
average velocity = (16km/hr)*(1hr/60min)*(1min/60s)*(1000m/… 4.44 m/s
distance = velocity*time = (4.44m/s)*6.8s = 30.2m
In one revolution the wheel will cover one circumference of the tire:
distance per revolution = pi*0.119m = .374m
number of revolutions = distance/distance per revolution = 30.19m/.374m = 80.7revolutions
average velocity = (16km/hr)*(1hr/60min)*(1min/60s)*(1000m/… 4.44 m/s
distance = velocity*time = (4.44m/s)*6.8s = 30.2m
In one revolution the wheel will cover one circumference of the tire:
distance per revolution = pi*0.119m = .374m
number of revolutions = distance/distance per revolution = 30.19m/.374m = 80.7revolutions
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Assuming constant acceleration, you need to figure out how far the bike went. First use the equation Vf=Vi+a*t Vf=32 Vi=0 t=6.8 solve for a a=4.7 m/s^2
now apply Xf=Xi+Vi*t+1/2*a*t^2 Xi=0 Vi=0 a=4.7 t=6.8 solve and Xf=108.7 m
now we need to know how far the bike goes in 1 rotation. so 100cm=1m 11.9 cm = .119m
The circumference of a wheel is 2*Pi*r or Pi*D.
The distance the wheel travels in 1 rotation is 0.373 m
.373*rotations=108.7
Rotations= 290.7
EDIT: My method is correct, My answer is wrong. I did not realize the Velocity was in km/hr, you need to convert the velocity.
now apply Xf=Xi+Vi*t+1/2*a*t^2 Xi=0 Vi=0 a=4.7 t=6.8 solve and Xf=108.7 m
now we need to know how far the bike goes in 1 rotation. so 100cm=1m 11.9 cm = .119m
The circumference of a wheel is 2*Pi*r or Pi*D.
The distance the wheel travels in 1 rotation is 0.373 m
.373*rotations=108.7
Rotations= 290.7
EDIT: My method is correct, My answer is wrong. I did not realize the Velocity was in km/hr, you need to convert the velocity.