SOLUTION: The wheel of a truck is making 280 rpm. Find the speed of the automobile in kilometers per hour if the radius of the wheel is 0.9m.

Question 1191874: The wheel of a truck is making 280 rpm. Find the speed of the automobile in kilometers per hour if the radius of the wheel is 0.9m.
Answer by Theo(13342) (Show Source): You can put this solution on YOUR website!
the radius of the wheel is .9 meters.
the circumference of the wheel is 2 * pi * r = 2 * pi * .9 = 1.8 * pi meters.
that's equal to 1 revolution of the wheel.
multiply that by 280 and you get 504 * pi meters in one minute.
a kilometer is equal to .001 * 1 meter.
504 * pi meters is equal to .001 * 504 * pi meters which is equal to .504 * pi kilometers.
since pi = 3.141592654 then .504 * pi kilometers is equal to 1.583362697 kilometers.
that's in 1 minute.
multiply that by 60 to get 95.00176184 kilometers per hour.
that should be your answer.
fyi:
since 1 kilometer is equal to 0.621371 miles, then the truck is traveling at 59.03133976 miles per hour.
this is not an unreasonable speed.
RELATED QUESTIONS
an automobile tire is 30 inches in diameter. How fast (rpm) does the wheel turn on the... (answered by stanbon)

An automobile can travel 200 kilometers in the same time that a truck can travel 150... (answered by josgarithmetic,MathTherapy)

The pedal sprocket has a radius of 4 in., the wheel sprocket has a radius of 2 in., and... (answered by lwsshak3)

a car travels 250 kilometers in the same time that a truck travels 225 kilometers. if the (answered by jorel1380)

What is the speed of an automobile in kilometers per hour if it is traveling 45 miles per (answered by krishna sharma)

please answer this question: a truck is moving at a rate of 105 kilometers per hour, and (answered by TimothyLamb,stanbon,josgarithmetic)

A car travels 250 kilometrs in the same time that a truck travels 225 kilometers. If the (answered by mananth)

the wheel on a truck are turning at 430 revolution per minutes as the truck travels 40... (answered by lwsshak3)

Speed of the car is 47.52 km / hr. A lorry wheel is rotating at 400 RPM. What is the... (answered by lwsshak3)