Solving Doubts on Rotational Motion

[freshbox]

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.

 

[ZxcvbnM2000]

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 .

 

[freshbox]

Thank you ZxcvbnM2000 for the reply.I want to ask can I use this equation v=rω to find the angular velocity as well?

 

[ZxcvbnM2000]

yes of course as long as you know the linear velocity and the radius ;p

 

[freshbox]

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?

 

[tiny-tim]

hi 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

… 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

 

[freshbox]

thank you tiny-tim for the explanation.