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Gravitation – Why acceleration due to gravity increases at pole instead of decreasing?

Acceleration due to gravity is found to decrease with increase in depth and vice versa. But, on the poles its value is more than as compared to that on the equator even though the depth is increasing.Why is this so? I know about the relation g is inversely proportional to R squared, but without this relation I can’t seem to b able to answer it with the depth relation.

AskedĀ Thakrei Ruivah

Answer

The force of gravity is inversely proportional to the the distance from the centre of earth and hence it is evident that at poles the acceleration due to gravity should be more since the polar radius is less that the equatorial radius.
Putting it simply, the entire mass of earth is attracting the object kept at the pole towards it centre and the distance from the centre is less. Therefore the force and hence the acceleration due to gravity will be maximum.

The decrease in g with depth is due to the fact that:
At any depth, the mass of earth coming within the sphere with radius equal to the distance from the centre of earth to the object under consideration will be responsible for the force of gravity and hence the value of acceleration due to gravity decreases.

Get more details fromĀ http://www.askphysics.com/variation-in-acceleration-due-to-gravity-g-with-depth/

Inelastic vs Elastic collisions

In class we we’re working on a lab, We had to shoot a stationary toy truck with a dart pulled back and giving it’s energy through a spring. We are given the mass of the dart and the truck, and found the amount of time the truck travelled for and its distance. I’m unsure which equation to start with in order to find the darts initial velocity.

ASKED IVIE

Answer:

This is based on Law of conservation of energy

Once light is generated at the source, where does it go ?

Once light is generated at the source, where does it go and when does it stop being light ?

Asked Laurence Simons

Answer:

Light is an electromagnetic wave. Once it is produced, it will travel out for ever if not absorbed or scattered. In vacuum there is nothing to absorb or scatter the light. So it will travel forever in vacuum. When it enters a medium it may be absorbed, reflected/scattered or transmitted.

You may refer to these links for more info

https://www.wired.com/2015/02/5-things-every-human-know-light/

https://van.physics.illinois.edu/qa/listing.php?id=21368

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