Rotational Inertia of a Wheel?

Question

A force of 15.78 N is applied tangentially to a wheel of radius 0.340 m and gives rise to an angular acceleration of 1.20 rad/s^2. Calculate the rotational inertia of the wheel.

Answer 1

Torque = Force applied x lever arm

Force applied F = 15.78 N
lever arm R = 0.34 m

torque = angular acceleration * I
I - rotational inertia
angular acceleration alpha = 1.2 rad/s^2

F * R = I alpha

I = F * R / alpha

I = 4.471 kg m^2

Answer 2

torque = I X @ where I=rotational inertia and @ = angular acceleration and torque = F X R = 15.78 N X 0.340 m

I = F X R / @