A truck with 48-in.-diameter wheels is traveling at 45 mi/h.

Question

(a) Find the angular speed of the wheels in rad/min.
rad/min

(b) How many revolutions per minute do the wheels make?
rev/min

Answer 1

one rotation = 2π(48) = 96π inches

in 1 hour it goes 45 miles
= 45x5280x12 inches
= 2851200 inches

number of rotations per hour
= 2851200/(96π) = 9453.8.. rotations per hour
= 157.563 rpm

= 157.563x(2π) radians /min
= 990 radians/min

Answer 2

45 mi/hr * 5280*12 in/mi /(2pi*48in/rev) * hr/60min * 2pi rad/rev = 3960 rev/min

rev/min = rad/min * rev/2pi rad, so divide 3960 by 2pi

Answer 3

Oops. Off by a factor of 2. I was using a radius of 48 in

Answer 4

Rats, I read it wrong also
radius should have been 24 , not 48

make the necessary adjustments in the above.

(time to go to bed)