







A dot on a child's car wheel 
20190428 

From julia: A wheel of a child’s car revolves at 10 rpm. A painted dot on the circumference of the wheel is 12 cm from the centre of rotation of the wheel. How far does the dot travel in 5 s, to one decimal place? Answered by Penny Nom. 





A rotating wheel 
20180824 

From Kay: A wheel with a radius of 7 inches is rotating at 4 revolutions per second. What is the
linear speed v, in feet per second? Answered by p. 





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. 





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. 





How do I calculate the roll diameter? 
20061105 

From Bob: if I have the RPM of the roll and the thickness of the web coming off the roll and the mm/min of the web how do I calculate the roll diameter? Answered by Stephen La Rocque. 





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. 

