4 ms·
when gravity is 1/6, a lower centre of gravity might not do as much as you think
by arccy 2y ago
when gravity is 1/6, a lower centre of gravity might not do as much as you think
- doormatt 2y agoSurely it just needs to be 6 times lower? ;)
- JoeAltmaier 2y agoI think that is entirely irrelevant. It just changes the speed of the topple. Does not affect at all the tendency to tip over?
- mathgeek 2y agoIt's been a while, but IIRC when we assume all other variables as constant, a lower center of mass (a) will decrease the denominator and thus increase the resulting necessary tipping force. Fₜ = (m × g × cos(θ) × b) / (a + b)
- hansvm 2y agoAdding to the sibling @mathgeek's comment, that's only true when there are no outside forces other than gravity. You can see that by taking the counter-argument to its extreme: with gravity of epsilon, even a gentle prod at the top of the object will topple it over.
- ForOldHack 2y agoPhysics 1A: the center of mass does not change. It is irrelevent. The tendancy to tip over is how wide the base is: look at the LEM. Big wide base. Did not tip over. None of them tipped over. They tip over faster on earth due to larger Earth's gravity and mass.
- hansvm 2y agoA big wide base with a center of mass magically very high off the ground would still be tippy though.
- wruza 2y agoWhen it's "very high off", the base stops being "big wide".
- JoeAltmaier 2y agoThat is exactly a description of why center of mass is the important variable. If the center of mass wanders outside the support point, it tips over. That's the whole deal right there!
- skykooler 2y agoThat just makes it six times as important!
- caycep 2y agoWhy didn't they use that bouncy inflatable ball technique the cute JPL robot used?
- deleted 2y ago[deleted]
- echoangle 2y agoMagnitude of gravity changes nothing as long as it’s not 0. Your CG is either inside the area covered by the hull of your leg contact points or it’s not. It won’t be stable in other regimes just because gravity is lower.
- gcanyon 2y agoI think it does change the situation when you're potentially dealing with lateral movement. In 1/6th of a g it takes less lateral velocity to topple over.
- russfink 2y agoRotational inertia does not change. Any horizontal V and a landing leg that sticks in the silt is recipe for disaster.