The hole would be completely straight and heatproof. 

Sorry if this has already been answered.....

As I understand it a traditional rollercoaster obtains the energy it needs to go round the ride from the initial drop.

Therefore is a rollercoaster that has its maximum number of riders  faster / slower or alter the experience due to it being heavy?

I'm new to this and although interested in Science never really paid much attention.

I'm sure the answer to my question will be connected to the rule you learn at school about the rate of falling being the same regardless of mass (or something like that!!) I obviously never really understood it so would like someone to answer me this question relating to something i like (rollercoasters) so I can learn something new today!

Thanks in advance!

I know that Io is volcanic because its elliptical orbit makes it stretch and contract causing friction. But if I look at energy transfer its kinetic to heat energy, but the kinetic energy comes from the elliptical orbit which only exists because of the gravitational pull of Europa and Callipso, yet gravity is one of the four forces of nature and not an energy. How? 

I have come to understand that the effects of gravity extend out almost endlessly but that the attractive force reduces in strength with distance.

Would two small objects, say, two bowling balls located in a completely empty universe, spaced, say, a light-year apart, eventually come together due to gravitational attraction? Is there a minimum mass these objects would need to reach each other gravitationally, or would it just be a question of time? There would be no other forces acting on these objects.

does the strength of gravity fluctuate due to the position of the sun and moon and there gravitational pull on you or is there an equal force on the earth which cancels this effect out?

Recently i have wondered about how the moon and sun affect gravity here on earth. I was wondering wether the force of gravity would change during night or day due to the position of the sun and the moon and their gravitational pulls. But just as I sat down to work this out (being the cool 16 year old I am) I also remembered that the sun and moon would also pull on the earth. so the question is would the pull the on the earth be the same as that on you and therefore cancel out any effects or do you infact become magically (or marginally) lighter at night or day due to this affect?

I'm sure the answer to this will be yes, but is there any experiment or astronomical observation that proves it?  For example, could I weigh a wire,  then weigh it again when a current is passing through it and see a difference?