







Revolutions per minute 
20141024 

From Edward: Hello; I have a 28.2 inch diameter tire; do not worry about engine RPM or gear ratios, please tell me what the RPM
of that tire is at 8 MPH and 64 MPH. Thank you.
Sincerely; Edward Answered by Penny Nom. 





Angular speed 
20140629 

From andrea: a wheel having a radius of 10cm rotates such that the linear speed at its rim is 30mls.
what is the angular speed of the wheel in rpm? Answered by Penny Nom. 





How many rpm does a 3.5 in. diameter wheel turn at 7 miles per hour? 
20111206 

From Al: how many rpm does a 3.5 in. diameter wheel turn at 7 miles per hour Answered by Penny Nom. 





Angular speed 
20101212 

From Jason: 7 in. pulley traveling @ 175ft/sec. What is the rpm? Answered by Stephen La Rocque and Penny Nom. 





The current in a river 
20080612 

From Joi: To approximate the speed of the current of a river, a circular paddle wheel with radius 4 feet is lowered into the water. If the current causes the wheel to rotate at a speed of 10 revolutions per minute, what is the speed of the current? Express your answer in miles per hour. Answered by Harley Weston. 





Is there a practical use for radian measure? 
20071026 

From Paula: Is there a practical use for radian measure in any profession? Which professions might us radian as opposed to degree measure? Answered by Harley Weston. 





Angular speed 
20070118 

From Cristina: A car is moving at a rate of 50 miles per hour, and the diameter of its wheels is 2.5 feet. a) Find the number of revolutions per minute the wheels are rotating. b) Find the angular speed of the wheels in radians per minute. Answered by Stephen La Rocque. 





What size pulley would I need? 
20061229 

From Chris: If I have a motor that's spinning at 950 RPM's with a pulley that's 6in diameter with a belt running to a generator, What size pulley would I need on the generator to make it spin at 3600 RPM Answered by Penny Nom. 





A rock on a string 
20031026 

From A student: a rock on a 4' string is rotated at 80 rpm. what is the linear speed in feet per second? in miles per hour? Answered by Penny Nom. 





PreCalculus 
20000809 

From Angela: Use absolute values to define the interval or pair of intervals on the real line.
<  ]    [ >
18 19 20 21 22 23 24 25 26
A car is moving at the rate of 50 miles per hour, and the diameter of its wheels is 2.5 feet. a) Find the number of revolutions per minute that the wheels are rotating. b) Find the angular speed of the wheels in radians per minute. Answered by Harley Weston. 

