How Fast Must a Bacterium Cling to a Spinning Jet Tire?

[mkwiatko]

Homework Statement

At takeoff, a commercial jet has a speed of 60.0 m/s. Its tires have a diameter of
0.850 m.
(a) At how many rpm are the tires rotating?
(b) What is the centripetal acceleration at the edge of the tire?
(c) With what force must a determined 10^-15 kg bacterium cling to the rim?
(d) What is the ratio of this force to the bacterium’s weight?

Homework Equations

angular velocity = v/r
centripetal acceleration = v^2/r

The Attempt at a Solution

I divided 60.0 m/s by .425 m to get (a). To get (b) I squared 60.0 m/s and divided it by .425 m. I am really stuck on (c). I am thinking the force it needs to cling to the rim is equal to the centripetal force. So, does that mean I just multiple it's mass by the centripetal acceleration? Any help would be appreciated.

 

[ehild]

Take care with the answer to (a). v/r is the angular velocity, not the revolutions per minute, rpm.
(c): you are right, the centripetal force is centripetal acceleration multiplied by the mass and that force is needed to move together with the tyre.

ehild