# Physics

posted by
**Matt** on
.

I am having trouble with the last portion of this question. If someone can help me, I would sincerely appreciate it.

A bicycle wheel has a radius R = 32.0 cm and a mass M = 1.82 kg which you may assume to be concentrated on the outside radius. A resistive force f = 147 N (due to the ground) is applied to the rim of the tire. A force F is applied to the sprocket at radius r such that the wheel has an angular acceleration of a = 4.50 rad/s^2. The tire does not slip.

a) If the sprocket radius is 4.53 cm, what is the force F (N)?

(mr^2)(4.5) = (r)(F)- (147)(.32)

(1.82)(.32^2)(4.5) = (.0453)(F)-(147)(.32)

= 1056.9

b) If the sprocket radius is 2.88 cm, what is the force F(N)?

(1.82)(.32^2)(4.5) = (.0288)(F)-(147)(.32) = 1662.45

c) What is the combined mass of the bicycle and rider (kg)?

I am not sure how to do this last part