Answer:
w=105rpm
Explanation:
The link between The lineal movement and and angular movement is V=w*r
w has units in rad/s, r is the radio of the rotating/moving element .
15 miles per hour= 15*63360 in/h= 950400 in/h= 15840 in/min
with the above relation we can use the link we were talking in the first paragraph.
15840 in/min=w*24in.
w=660 rad/min
w= 660 /(2 pi) rpm= 105rpm