
#1
Oct3111, 11:25 AM

P: 138

1. The problem statement, all variables and given/known data
9. A force can change angular rotational if it acts through: a. the axis of rotation *b. a lever arm tangential to the direction of rotation c. a moment arm parallel to the axis of rotation d. none of these 2. Relevant equations n/a 3. The attempt at a solution I would like to understand why b is the correct answer. 



#2
Oct3111, 12:11 PM

P: 1,084

I guess we could start with why it isn't a or c. Angular momentum is changed when Torque is applied. If you apply a force through the axis of rotation, then r is 0. if you apply force through a moment arm parallel to the axis of rotation then torque is also zero since
τ = F x r τ = Frsinσ since F and r are parallel, the angle is 0, therefore the torque is 0. If you applied it tangentially, then the σ value will be 90 and sinσ will be 1. 



#3
Oct3111, 12:30 PM

P: 138

Got it...thanks!!




#4
Oct3111, 12:36 PM

P: 1,084

Rotational Motion change angular rotational 


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