does size and shape affect gravity?
2007-01-21 18:15:10 · 8 answers · asked by 234retgf 3 in Science & Mathematics ➔ Physics
It absolutely does - one of the early proofs everyone should do in physics is that for a homogenous sphere the force acts as if it comes from the center. The fact that this needs to be proved for a sphere indicates it is not necessarily true. If the mass is sufficiently far away then the shape can be ignored.
Doc B has the right idea - imagine the mass of the earth in a large flat plane. If you were hovering over the middle of it you would figure the force by integrating over the surface using the equation f = ma. For all but the point directly underneath the mass, there are both horizontal and vertical components, and the horizontal components will cancel out.
Another example: use the earth's mass to form a hollow spherical shell the size of the earth. If you were standing on the outside you would find no change from our current gravity. At every point inside, the force would be 0 - it would cancel out completely.
2007-01-21 20:41:46 · answer #1 · answered by sofarsogood 5 · 0⤊ 0⤋
I agree with the people who say size and shape don't matter (it's really about mass and distance), except for one thing.
If there was, say, a huge cylinder (can with no lids) floating in space, it would exert gravitational force on distant objects essentially like a solid ball of the same mass. But if something were to move into the cylinder, some of the cylinder's own gravity would cancel other bits of its own gravity, reducing the net effect (to zero at the center).
Likewise, you could experience less gravity hiking through the base of a very deep ravine than you would flying along the top of it, for the same reason.
The size and shape of an object make this strange effect possible, or not.
2007-01-21 18:41:23 · answer #2 · answered by Doc B 6 · 1⤊ 0⤋
nope. Gravity's affect on an object is a direct result of an object's mass. The more mass, the more particles gravity has to exert its feeble force upon. Why then do certain object's fall faster than others when dropped? That only happens when things such as air resistance come into play. I forget which astronaut it was, but one of them took a falcon feather and a hammer and released both at the same time while on the Moon. They both fell at same rate and landed on surface at same time.
So, in a vacuum, and disregarding any other forces, an aircraft carrier and piece of paper would fall at the same rate in the same gravity well.
2007-01-21 18:31:05 · answer #3 · answered by quntmphys238 6 · 0⤊ 0⤋
Size?. How do you define it?. You can have a 10 m wide sheet and 2 m wide sheet with the same 'mass'.
Gravity is dependent on 'mass (m)' and 'acceleration due to gravity (g)'. g is always constant. m doesn't vary with shape and size.
So, answer is no.
Then you might ask, then why a 10 m wide sheet falls later than a 2 m wide sheet of same 'mass'. Here Force of gravity is the same which is 'mg'. But according to newton's another law "everybody continues to be in it's state of motion unless compelled by an external force". Here external force is important as the air pressure from beneath will be more for a 10m wide sheet than a 2 m sheet due to surface area.
2007-01-21 18:27:57 · answer #4 · answered by jaggie_c 4 · 0⤊ 0⤋
It actually does but the effect is so minute it isn't considered. Distance between the objects is one of the key concerns with gravity.
If you are interested in gravity search the web for the gravity test canada is doing. They are getting readings from all over their country to see what the gravity is across the country. I added one link that I found real quick that looks like it explains what Canada is doing.
2007-01-21 18:28:30 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Density has a greater factor on the effect of gravity, for the same size block of wood and a block of lead , the lead is more dense and weights more than the wood block. but a bigger piece of wood would weigh more than a smaller piece of similar wood. so size does and now shape..... I think of similar material shape wouldn't matter but the volume of the piece would, Similar volumes in different shapes should be the same Weight (or pull) unless they were falling or moving and had Air, water, or moving resistance involved.
2007-01-21 18:33:33 · answer #6 · answered by S h 3 · 0⤊ 0⤋
No. G remains constant at a place.
2007-01-21 18:24:23 · answer #7 · answered by cristina m 2 · 0⤊ 1⤋
In a vacuum, no.
2007-01-21 18:20:05 · answer #8 · answered by Jon A 4 · 0⤊ 1⤋