# Torque Question airplane wheels

1. Dec 12, 2007

### wannabenerd

1. An airliner lands with a speed of 45.0 m/s. Each wheel of the plane has a radius of 1.25 m and a moment of inertia of 110 kg·m2. At touchdown the wheels begin to spin under the action of friction. Each wheel supports a weight of 1.40 x 10^4 N, and the wheels attain the angular speed of rolling without slipping in 0.53 s. What is the coefficient of kinetic friction between the wheels and the runway? Assume that the speed of the plane is constant.

2. Relevant equations:
v=rw
I= 2/5MR^2
F=ma
friction=un
sum of forces?

3. I started by finding the angular velocity. using v=rw, i found it to be 36 rad/s. Then, I found the angular acceleration by doing w=w+at and a is equal to 67.925 rad/s^2. I don't know what to do next? Should I do the F=ma? But a is the linear acceleration and I don't know. I'm really confused about this problem because friction acts on four wheels or something? I don't know. Help please?

2. Dec 12, 2007

### Office_Shredder

Staff Emeritus
The rotational version of F=ma is T=W*ar where ar is rotational acceleration, W is the moment of inertia, and T is the torque