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Q & A: how big is gravity?

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Most recent answer: 02/07/2015
Q:
My son got a physics question wrong and I'm trying to understand it. The question "is gravity greater on the bowling ball or the baseball?" He answered gravity pulls the same on both and got it wrong. I understand Newton's law that heavier objects pull harder on each other, however if both the above items are on the earth the gravity exerted on them by the earth does not change, the gravity of the heavier object simply pulls harder on the earth right? So to ask does gravity pull harder is a yes and no answer. The gravity of the earth does not change the mass of the heavier object pulls it faster. Yes or no?
- Dave (age 36)
Albert Lea, MN US
A:

Probably the question meant "the force of gravity". That's what's usually meant by "how much gravity pulls". Since the force is proportional to the mass, the bowling ball has a higher force on it. On the other hand, the acceleration of the bowling ball will be the same as that of the baseball, ignoring the little bit of air friction.  Someone might mean something about acceleration rather than force by "how much gravity pulls". In that less common way of speaking, your son's answer would be ok.

Mike W.


(published on 02/07/2015)

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