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spoon
Dec1-04, 09:46 PM
An 8.90-cm-diameter, 310 g sphere is released from rest at the top of a 2.00-m-long, 17 degree incline. It rolls, without slipping, to the bottom.

a) What is the sphere's angular velocity at the bottom of the incline?
b) What fraction of its kinetic energy is rotational?

If someone could help me out, it'd be great...I'm not exactly sure how to tackle this problem...

thermodynamicaldude
Dec1-04, 09:57 PM
To start off...

Gravitational Potential Energy = Linear Kinetic Energy + Rotational Kinetic Energy

...Rotational Kinetic Energy = 1/2 I w^2

w(its called omega) = v/r

I of Sphere = (2/5)mr^2...

..thusly...Rotational Kinetic Energy = (1/2)[(2/5)mr^2][v/r]^2...which simplifies to..
....(1/10)mv^2

Work from there.....

Pyrrhus
Dec1-04, 10:03 PM
anaylizing both movement rotational and linear we should consider a kinetic energy of the sum of both the linear of its center of mass and the rotational. Apply Conservation of Mechanical Energy because it's pure rolling motion (no slipping).

spoon
Dec1-04, 10:20 PM
I kind of get what you're saying but I'm still sort of lost?

spoon
Dec1-04, 10:30 PM
Actually now I got part A...I just need part B...
Thanks for the help by the way