Rotation, angular momentum and inertia

aks_sky
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The rotor of an electric motor has Im= 2 x 10 -3 Kg.m2
about its central axis. The motor is used to change the orientation of a space probe in which it is mounted. If the axis of the motor is mounted parallel to the axis of the probe (Ip= 12 Kg.m^2) calculate the number of rotations required to turn the probe through 30 degrees about its axis.


** I have tried the formula for anuglar momentum and torque here also i have tried to find the ratio between the two bodies but i do not get the correct answer. The answer should be 498 revs but i don't get it right. What else can i try?
 
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aks_sky said:
The rotor of an electric motor has Im= 2 x 10 -3 Kg.m2
about its central axis. The motor is used to change the orientation of a space probe in which it is mounted. If the axis of the motor is mounted parallel to the axis of the probe (Ip= 12 Kg.m^2) calculate the number of rotations required to turn the probe through 30 degrees about its axis.


** I have tried the formula for anuglar momentum and torque here also i have tried to find the ratio between the two bodies but i do not get the correct answer. The answer should be 498 revs but i don't get it right. What else can i try?


Hi aks_sky! :smile:

Just use conservation of angular momentum …

it starts zero, so it stays zero! :wink:

(and remember 30º = 1/12 of a revolution)
 
sweet.. all sorted.. thank u
 

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