Rotational Intertia of a rotating Space Station

[slingshotnz]

Homework Statement

Four rockets attached to a (wheel) space station exert a force of 65.5N to rotate it . The space station's angular velocity is increased at a constant acceleration of 3.63 x 10^-3 rads^-2. Each rocket is 11.2m away from the centre. Calculate the rotational inertia of the system.

Homework Equations

τ=Iα , others unknown.

The Attempt at a Solution

Torque of all 4 rockets. (65.5N * 11.2) * 4 = 2934.4N
since τ=Iα, I=τ/α hence I= 2934.4/3.63x10^-3 = 808374.7Kgm²

Can anyone confirm if this is the correct method.

Thanks.

 

[SteamKing]

The units for inertia are wrong. What are the derived units for the Newton? (Hint: F = ma)

 

[slingshotnz]

Sorry Kg metres squared?. Other than that does the working look fine? I appreciate the advice.

 

[haruspex]

Not sure, but I think SteamKing may be referring to this item:

Torque of all 4 rockets. (65.5N * 11.2) * 4 = 2934.4N

force in N * distance in m gives what units?
(Your method and answer look ok.)

 

[SteamKing]

I missed the torque units. But the units for moment of inertia should be kg-m^2. OP originally had kg-m^-2.