independant trials question (1 Viewer)

[abdog]

1.Planet X has twice the mass and half the radius of Plant Y. What is the ratio of the weight of a 10kg mass on planet X to its weight on planet Y?

2.Michelson and Morley expected to see a shift in an interference pattern in their experiment. They were destined to get always get a null result. Why?

 

[Amundies]

1. Gravity = Gravitational Constant x Mass of planet / (Radius of planet)^2. If you double the mass, you double the force of gravity. If you halve the radius, you multiply the force of gravity by 4. Putting these two together, you get the force of gravity to be 8x greater on Planet X. Since W=mg, on Planet Y W=10g and on Planet X W=10x8g=80g. Planet X weight: Planet Y weight is 80g:10g which can be simplified to 8:1.
I think that's right...

 

[abdog]

How does halving the radius multiply the force of gravity by 4? Shouldn't it be just 2? Can you show me how?

 

[Hoskiies]

Because there's a square on the bottom. Thus when you pug you half (0.5) and you square it you get 0.25. So its 4 times less than originally. Eg, Let Radius X be A therefore Radius Y is A/2 so (A/2)^2 = A^2/4

2. At that time they believed that the interferometer was accurate enough to detect the aether wind which will affect the speed of light. By doing so when rotating 90 degrees, they expected a shift in interference pattern (the light traveling with the aether is now against it and vice versa) compared to the interference pattern at the original position hence they got a 'null' result. They performed the experiment at multiple locations and got the same results, this did not mean that the model of the aether was wrong but merely floored.

 

[someth1ng]

Because there's a square on the bottom. Thus when you pug you half (0.5) and you square it you get 0.25. So its 4 times less than originally. Eg, Let Radius X be A therefore Radius Y is A/2 so (A/2)^2 = A^2/4

2. At that time they believed that the interferometer was accurate enough to detect the aether wind which will affect the speed of light. By doing so when rotating 90 degrees, they expected a shift in interference pattern (the light traveling with the aether is now against it and vice versa) compared to the interference pattern at the original position hence they got a 'null' result. They performed the experiment at multiple locations and got the same results, this did not mean that the model of the aether was wrong but merely floored.

That doesn't answer the question.

The answer should be based more around the fact that the speed of light is constant in all inertial frames of reference and thus, for the experiment, the distance was the same for both and so, light must reach the detector at the same time.

 

[Hoskiies]

That doesn't answer the question.

The answer should be based more around the fact that the speed of light is constant in all inertial frames of reference and thus, for the experiment, the distance was the same for both and so, light must reach the detector at the same time.

Yea, I see now Thanks