# Rotational Motion

by freshbox
Tags: motion, rotational
 P: 284 Hi guys, I have a few doubts on Rotational Motion and hope someone can help me out. This 3 formula is for finding angular velocity, angular acceleration and angular displacement right? ω=ωi+αt ω²=ωi²+2αδ δ=ωit+1/2αt² And this 3 formula is for finding the linear velocity/acceleration/displacement in a angular shape? s=rδ v=rω α=rα Thanks.
 P: 64 If you have no problems on linear acceleration then then only thing that changes in rotational motion is that u becomes ω , a becomes α , x becomes θ . In both of your questions , the answer is yes .
 P: 284 Thank you ZxcvbnM2000 for the reply. I want to ask can I use this equation v=rω to find the angular velocity as well?
 P: 64 Rotational Motion yes of course as long as you know the linear velocity and the radius ;p
 P: 284 Ok thank you for the explanation and help. Out of topic abit, if a rock is thrown downward from the top of a building, the velocity I can set it as -ve or +ve, and usually people set it to +ve for the working to be easier, am I right?
HW Helper
Thanks
P: 26,148
hi freshbox!
 Quote by freshbox This 3 formula is for finding angular velocity, angular acceleration and angular displacement right? ω=ωi+αt ω²=ωi²+2αδ δ=ωit+1/2αt²
only for constant acceleration (just like the linear case)
 And this 3 formula is for finding the linear velocity/acceleration/displacement in a angular shape? s=rδ v=rω a=rα
s=rδ works only for constant ω

the other two always work
 Quote by freshbox … if a rock is thrown downward from the top of a building, the velocity I can set it as -ve or +ve, and usually people set it to +ve for the working to be easier, am I right?
yes, so long as you're careful to adjust the sign of g to match
 P: 284 thank you tiny-tim for the explanation.

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