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M2 moments equilibrium toppling question

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Im not sure how to even attempt this
(Part 2)
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Reply 1
Avatar for pri12321
pri12321
3
Original post by tavtavtav
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Im not sure how to even attempt this
(Part 2)


I would take moments about the point of the base touching the ground using the centre of mass you found in the previous part and the weights. If the resultant movement is anticlockwise then the toy will move so the rod is upwards
Reply 2
Avatar for tavtavtav
tavtavtav
OP
9
Original post by TheBride
I would take moments about the point of the base touching the ground using the centre of mass you found in the previous part and the weights. If the resultant movement is anticlockwise then the toy will move so the rod is upwards

But without knowing the reactions and only the centre of mass I won't be able to get a resultant moments.
Reply 3
Avatar for pri12321
pri12321
3
Original post by tavtavtav
But without knowing the reactions and only the centre of mass I won't be able to get a resultant moments.


Was the COM for the whole toy or just the base? I can't see from the pics
Reply 4
Avatar for oShahpo
oShahpo
20
wrong post. sorry/
Consider this: The toy can only topple in two ways, around the black ball part or the semicircle part. If it was going to topple around the black ball/dot part the COM would need to be super far to the right, this is obviously ridiculous. Thus the only real way its going to topple is around the semi circle, and this only is going to happen if the COM is further left of the contact point between the semi circle and ground. You can use the known lengths to get the angle, and trig to work out the horizontal distances, and compare to see if the COM is left of the critical point or not.
Reply 6
Avatar for tavtavtav
tavtavtav
OP
9
Original post by TheBride
Was the COM for the whole toy or just the base? I can't see from the pics


Whole toy
Reply 7
Avatar for pri12321
pri12321
3
Original post by tavtavtav
Whole toy


Then I agree with the post above; I think it's just a case of working out the trig and seeing if the COM is to the left or not :smile:

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