Does a rollercoaster go faster empty or with a full load? why?

Question

I know the answer....I just want to see who else does....i will give the best answer award to the first correct answer

what happened to kinetic energy=gravitational potential energy - friction - aerodynamic drag - (any other non-conserative force)?

Answer 1

There are several factors.
Gravity will effect both the same, No change.
Wind resistance will slow it, greater mass will tend to overcome the resistance created by wind so loaded wins.
Friction (wheels on the track). Greater mass will have a negative effect so heavier looses. (the efficiency of the rollers and bearings are NOT given)
I'll put MY money on friction being more important than wind resistance and op for the EMPTY coaster going faster.
More data required!

Answer 2

Wow, cool, this is sort of an puzzle contest huh?

Okay, first ignoring friction and drag, the speed would be the same, by Conservation of Energy ... the potential at the top of the hill has to equal the kinetic energy at the bottom, thus v=sqrt[2gh] and mass cancels.

But we can't ignore friction and drag ...

For rolling friction, as the mass increases with people in it, the normal force of the track increases, which increases the rolling frictional force of the wheels thus slowing the coaster down. BUT, when you draw a little sketch, you see that the extra weight is directed mostly down, since roller coasters are usually pretty steep (that's why they're fun) and thus the rolling friction is not strongly dependent on weight with steep roller coasters.

Now, for air frictional drag, a full roller coaster has a larger front profile than an empty one, and this will be normal to the direction of movement. Given the speed domain (near freefall for a very fun roller coaster) this will make the biggest contribution in changing the speed, similar to a skydiver wearing a floppy suit as opposed to a skin-tight suit, which can nearly halve the skydiver's terminal velocity. A full roller coaster car will slow it down due to air drag much more than the contribution of rolling friction.

There are other considerations, like deformation of the wheels with increased weight, increased metal heating with increased weight, and changing of the coasters center of gravity. But I estimate that these are small compared to the effects of air drag.

Thus, the empty one should reach the bottom of the hill faster than the full one, especially on steep hills, assuming the initial speed at the top of the hill is equal for both scenarios ... which it won't be, but we can assume.

Now, all of this is exacerbated if you now consider the overall speed of the coaster over its entire course. Suddenly the frictional force on the wheels is much higher at the bottom of the hill for a full load, the frictional load is much higher on climbing smaller hills after the first big hill, etc..

So, the rollercoaster is faster empty.

Answer 3

The full one will go faster.

All other things being equal, a full and empty one would reach the end at the same time according to basic physics. However, friction means all things are not equal. Since air friction depends on speed and shape (but not mass), there will be about the same amount for both, so the heavier one (more inertia) will be less affected by it than the lighter one. Rolling friction, on the other depends solely on weight, so it will be proportionately greater than the empty one and should not affect the outcome significantly.

Come to think of it, the same phenomenon is discussed by fighter pilots as "energy." However, they use the term inaccurately--they say a heavier plane has more energy (true) so when two planes zoom climb, the heavier one goes higher (true) because it started with more energy (false). It DID start with more energy, but that should be exactly offset by its increased mass, and they should zoom climb to the same height. However, the lighter plane is affected proportionately by air friction more, so the heavier plane does out zoom the lighter plane.

Answer 4

It will go at the same speed, more or less -- the speed is due to the acceleration of gravity which is constant. However, weight on the wheels might cause more friction, and air resistance from all the people might slow it down when full.

Answer 5

Gravity is the key word here. Just like a truck with a load of 80,000 lbs. going down a steep mountain. Stay out of the way, because the weight of the load is pushing it down hill.
Same thing happens in a Roller coaster.

Answer 6

It would go faster FULL.

As you should know by Newton's laws, two items falling will always have the same acceleration no matter what the mass. If one item is heavier however, it more easily overcomes friction and air resistance which would slow it down more if it was lighter.

Answer 7

Niether.

1/2 m v^2 = m g h.

v = sqrt(2gh)

Potential energy is changed into kinetic energy. Mass is canceled out.

Answer 8

with a full load. The extra weight makes adds more momentum

Answer 9

Equivalence Principle - no difference.
Friction - faster empty.
Air resistance - faster full.
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Faster full

Answer 10

i believe empty

less people, less weight

less weight, faster speed