If 2 people are on a water slide, which goes faster? The lighter or the heavier person?

Question

Which body would travel faster?

Answer 1

If shape and volume are the same the only variable is weight, then they would travel at the same speed, but the hevier person would hit the water with greater force.

Since the heavier person has a larger profile (looking from the front) he would have more wind resistance slowing him down.  The total surface of the heavier person touching the slide would also slow him down.  But if he was a real greaseball, that would work in his favor.  I also would think a thicker layer of hair would benefit him also.

Answer 2

The lighter person because there will be less friction between them and the slide due to the weight.

Answer 3

From my days at the waterparks i always see the heavier people win races on the slides and i think i can use physics to explain my observaions

Objects fall at the same speeds in a vacuum. Drop a feather and hammer on the moon and they land at the same time http://www.youtube.com/watch?v=5C5_dOEyA...

However i am assuming the slide was at a water park on Earth!

Here we have frictional resistance on the slide and air resistance as air blows in your face.

Both of these types of resistance slow you down on the slide and so the question is who gets slowed down the least by these resistances.

A good water slide has a good flow of water and is very slippery and fast, which makes it so much fun and means we don't have to worry about friction (although a heavier person would experience more friction).

Just considering air resistance and not friction we can say the heavier person will go faster, just as a spanner falls quicker than a feather in our atmosphere.

Mathematically speaking we have

Total accelaration = (force due to gravity - force of air resistance) /mass

force of  air resistance is the same for both sliders ( only function of speed)

forece due to gravity = Mass * acceleration due to gravity

acceleration due to gravity ==9.81 m/s/s

so the heavier person has a greater force due to gravity (more commonly known as weight) and greater total acceleration

Of course there are other factors to consider such as aerodynamics of the slider, materials of the swimsuit and quality of the slide. So there is no reason for the lighter person to give up on trying to win the race!

Answer 4

I would guess the heavier.

Answer 5

my vote is for the lighter person because there would be less friction/drag to slow him down.  a heavier person will reduce the water cushion between him and the slid.

Answer 6

I'd say the lighter person, seems obvious.

Answer 7

If it's a straight slide, the heavier person would be faster because the lighter person has so much less inertia that it would be easier to slow down.

If it's a curved slide the heavier person has so much inertia that he would slow down too much around the curves

Answer 8

Well first of all, mass alone is never a factor when dealing with free fall. So if this was a simple free fall, like jumping out a window, neither would fall faster.

However, being on a water slide, the heavier person would caouse more frictional resistance on the water slide, and onto the water itself. So the lighter person falls faster.

Answer 9

there are too many unanswered variables in your question

do they have equal aerodynamics,

when you say lighter and heavier do you mean more and less mass

too many things

if they had the same aerodynamics then the heavier person would go faster,

Answer 10

It would be a draw if all other things are equal.  Here's why....

f = ma = W - F; where f is net force acting on each slider of mass m, a is the acceleration down the slide, W is the weight = mg sin(theta), and the friction force F = kN = kmg cos(theta) where k is the coefficient of friction and theta is the slope of the slide.

Thus ma = mg sin(theta) - kmg cos(theta) and a = g (sin(theta) - k cos(theta)).  And there you have it.  They would both come down at the same acceleration because their masses, and therefore their weights, do not affect the acceleration rate.  

The only factors we can control to change the accelerations are theta, the angle of the slide, and k, the coefficient of friction.  So if we want the sliders to go faster, we tilt the slide more or we run water over it to reduce k, the coefficient of sliding friction.

PS:  Belly or back, regardless, if the coefficients of friction remain the same and the slide angle is not changed, then it will be a draw.  There are a few things that could change the coefficients.  For example, one of the sliders might be wearing a full body suit and the other is wearing a bikini.  In which case, I'd suspect the coefficient for the suit-to-slide contact would be higher than for the skin-to-slide contact.  But that might not be the case if the full body suit is made of those new materials that cut down on water drag, like those worn by the olympic swimmers.  In any case, "all other things equal" they would descend at the same rate of acceleration and the end velocities would be the same...it would be a draw.