- #1
frazdaz
- 13
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Homework Statement
A uniform solid sphere rolls down an incline without slipping. If the
linear acceleration of the centre of mass of the sphere is 0.2g, then what
is the angle the incline makes with the horizontal? Repeat for a thin
spherical shell.
Homework Equations
[tex]\sum \tau = I \alpha[/tex]
[tex]I_{ball} = \frac{2mr^2}{5}[/tex]
The Attempt at a Solution
Moments about the tipping point:
[tex]mgrsin\theta = \frac{2mr^2}{5}\alpha[/tex]
Don't think this is going anywhere but I can't think of any other way to include moments of inertia.
Just thought, this moment of inertia is from the centre of the ball, not the tipping point. Correct?
So, by the parallel axis theorem,
[tex]mgrsin\theta = (\frac{2mr^2}{5} + mr^2)\alpha = \frac{7mr^2}{5}\alpha [/tex]
Which hardly helps
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