New to this forum! help on some problems

[math_geek2010]

hey i was wondering if i could get a little help with rotation problems... with the angular velocity and all. so far i know Θ=s/r and V=wr
i need help with converting rpm to mph and vice versa.
one problem from a test: A bicycle with 27 in. diameter wheels is going 23 mph. At what rate are the wheels rotating? (how would i solve this problem) also they want the answer in RPM.


thanks for any help,
math_geek2010

[Gurgle]

I'm not sure if this is right, but I'll try!

23 miles*5280ft*12in/60

Gives you the units in/per minute. Divide by the circumference to get the frequency. It should come out to 286.337.

I believe using physics it works like this, V= Omega R, so V=2piR/T where T is the period. Revs per minute utilizes the units 1/min which is 1/T. and is called the frequency
So using the units that I prefer.

23 mi 5280 ft 12 in 2.54cm 1m 1 hr = 617 m/min
1 hr 1 mi 1ft 1 in 100cm 60 mins

Using the conversion above, make sure the diameter is in meters.

617=Pi Diameter frequency

Also, I think this needs to be moved either to UIL mathematics or Science. ----> moderated

[math_geek2010]

hey sorry for the REALLY LATE reply..... thanks thats what i needed!