if they were both at the top of a hill, also has equal weight and the riders t he same weight , would the size in wheels make any difference or would the smaller wheels go round faster? would a skateboard be slower than a bike?
2006-10-20 03:58:56 · 18 answers · asked by robinhood 2 in Science & Mathematics ➔ Physics
the bike with the lager wheels would b fastest. it can travel farther b/c of it's size. it may not have the same amount of roations per minute as the smaller bike but it does have distance. there fore....the bike with larger wheels is faster.
2006-10-20 04:02:41 · answer #1 · answered by <3Kiira<3 2 · 0⤊ 3⤋
I have to agree with smartypantsmbcanada. They will both arrive at the same time. If all things are equal except the size of the wheels...it will appear that the small wheel is traveling faster than the big wheel but they will be actually covering the same distance at the same time if they are only coasting. The only time there will be a difference is if an equal force is applied to both bicycles then equal rotation of both size wheels will cause the large wheel to cover more ground than the smaller wheel. Simple physics. Good question
2006-10-20 11:58:13 · answer #2 · answered by dave19644 2 · 0⤊ 0⤋
three things have to be taken in for consideration
1/ gravity
2/ friction
3/ all modes of transport are coasting
if there was no friction from the tyres/wheels touching the road or wind drag from the posture of the riders on the modes of transport both bikes and skateboard would arrive at the same time.
however this not the case. for sake of arguement we say that the the wind drag is equal on all three modes of transport so we can cancel this out as one of the factors.
so friction of tyres/wheels on the surface is what we work with.
the skateboard wheels are wider and smaller than the tyres of the bikes and there are four of them, to much friction the skateboard loses straight away.
next the arc of the small tyre bike is smaller than the larger tyre bike, therefore more of the smaller tyre is in contact with the road and therefore more friction, so the smaller wheel bike is gone as well leaving you with the larger wheel bike to reach the bottom first.
note
say the small tyre is half the size of the large tyre it would have to do two revolutions to the one revolution of the larger. even though it's rotating twice as fast as the large tyre it still only covering the same distance.
say one revolution of the bike tyre cover 1 meter how many revolutions of the skateboard wheel has to do to cover the same distance?
so even though the smaller wheel is going faster than the larger one, that does not mean it's covering the same distance.
2006-10-20 23:42:03 · answer #3 · answered by sycamore 3 · 0⤊ 0⤋
the only difference in this case would be in the angular momentum in the wheels. if they were travelling at the same speed then the larger wheels would have a larger angular momentum meaning it would accelerate slower.
The force would be the same and
force=rate of change of momentum
Angular momentum = moment of inertia * angular velocity
where moment of inertia = 1/2 M R^2 (I think this is the correct one for a wheel)
and R is the radius.
So unless the bike with the larger wheels also had much lighter wheels then the one with smaller wheels will accelerate faster.
It is also worth noting that the terminal velocity would be the same for both.
Michael_ H is probably right because I haven't considered bearing friction and stability(thicker tyres needed). But I am a theory guy, I don't live in the real world.
2006-10-20 11:10:13 · answer #4 · answered by Mike 5 · 1⤊ 0⤋
bigger the wheel, faster the ride down.
Its because of road slip, bearing friction, stability and wind resisitance.
Take a look at any of the winning downhill go-cart racers. Flippin big wheels.
If you're unsure how to judge these things just exagurate them. If you had a bike with 1 inch diameter wheels you'd soon agree that a 20 inch diemeter wheel will free-coast down the hill faster ( or at least i hope you can see that easily )
Mike below is right in what he says but wrong in answer to your question. Sure, the small wheel bike will have faster acceleration....for the first half a second....that wasn't the question.
2006-10-20 11:08:40 · answer #5 · answered by Michael H 7 · 1⤊ 0⤋
since both bikes are at the same height, they have the same potential energy give by mass x gravitational Field strength x change in height, if we ignore wind Resistance and friction
+ imagine the slope of the hill has no bumps etc, then all of this energy goes into their kinetic energy given by, .5 x mass x velocity^2, so
mass x gravitational Field strength x change in height = .5 x mass x velocity^2
as you can see the mass cancels so its independent of mass!
so the velocity^2 =2 x gravitational Field strength x change in height
therefore the will both have the same velocity at the bottom, and so have taken the same time to reach the bottom. as for the different sized wheels, it just means the smaller wheels will have the greater angular velocity since they have had to turn many times more than the larger wheel, because its circumference is smaller but its trying to cover the same distance.
2006-10-20 14:57:30 · answer #6 · answered by s 2 · 0⤊ 0⤋
If you make the typical gedanken-experiment assumptions of perfect conditions and zero friction, the small wheels would win. All candidate vehicles start with identical position, mass, and potential energy. When they reach the bottom, all the potential energy is gone and has all been converted into kinetic energy. For the big wheels, more of that kinetic energy is rotational, less in forward movement. Further, at the start, less energy is available to accelerate the mass forward, so its linear acceleration is less, and it falls behind immediately with no way to catch up.
In the real world, the size of the wheel is just one of many factors.
2006-10-20 15:06:26 · answer #7 · answered by Frank N 7 · 0⤊ 0⤋
the 1 with big wheels if the hill is not steep because the bicycles with big wheels has more resultant force then that of bicycle having small wheels but wait...................
a= 9.8meters per second square......... so if the bicycle is free n it is not being paddled,,, n hill is not that much steep then both will reach the ground at the same time
but if the hill is steep then a bicycle with small wheels will reach the ground first bcus the bicycle with small wheels can be controlled easily than that of big wheels
2006-10-20 23:25:35 · answer #8 · answered by Anonymous · 0⤊ 0⤋
As the question is to do with speed of descent - this is dependent on the friction incurred by either machine. All other factors being equal the larger wheeled bike should incur less drag as the wheels turn less often.
2006-10-20 11:11:52 · answer #9 · answered by ? 1 · 2⤊ 0⤋
assuming a perfect world - no wind resistance no friction and each bike is of equal weight - then they would reach the bottom at the same time. without friction the high frequency of rotation of the smaller wheel does not matter
gravity acts on them the same.
2006-10-20 11:24:41 · answer #10 · answered by smartypantsmbcanada 3 · 0⤊ 0⤋
The weight if a hundred lb. falls just as fast as a 10 lb. There are several problems the size of the wheel means nothing,it is the friction. try again
2006-10-20 11:06:55 · answer #11 · answered by JOHNNIE B 7 · 0⤊ 2⤋