2 cars of identical overall mass are in a race on a straight track.

 

Car A has 10% of it's mass in the body and 90% of it's mass in the wheels (hypothetically)

 

Car B has 90% of it's mass in the body and 10% of it's mass in the wheels (hypothetically)

 

Which car will win assuming they both have the same power and are driven identically etc. ?

 

I think car B would win (but am not certain).

Good work Nelson! You're one seriously obsessed guy!

 

New question. If car A has a low MASS collection of small dog clutch engaged gears attached to it and car B has heavy lumps of metal churning a puddle of ATF, which one would be the faster...

 

I'll get my coat.

but if its a very short race wouldnt the car with less mass at the wheels just spin where as the car with the heaver wheels would not spin, or am i just a dumb canadian lol

but if its a very short race wouldnt the car with less mass at the wheels just spin where as the car with the heaver wheels would not spin, or am i just a dumb canadian lol

 

Please don't get all technical on us it's bed time over here :rolleyes:

lol very sorry

Car B would win. Car A has more inertia to get the wheels moving so takes longer hence slower acceleration. Top speed of car B would probably be less than car A as well due to car B havung greater resistance in turning motion at the wheels.

 

CORRECTION:

 

Top speed of CAR A would probably be less than CAR B as well due to CAR A having greater resistance in turning motion at the wheels. (I was tired!!!)

Top speed of car B would probably be less than car A as well due to car B havung greater resistance in turning motion at the wheels.

 

Don't you mean car B would be faster ?

 

also, the more the mass of the wheels is towards the centre the better. Centre point of the wheels is equivalent to any other non-rotating part of the car. Further out = takes more energy to turn. I think this wud reduce top speed as well as acceleration.

... Further out = takes more energy to turn. I think this wud reduce top speed as well as acceleration.

 

 

Which is EXACTLY what I was trying to say ;) LOL

Thought the title said "interesting" hypothetical problem ???

Apparently I need to get out more ! :p

Lol, yes! :tongue: :rofl:

the concensus of thought now here at work is that both cars wud reach the same terminal velocity. The lighter wheels wud only make car B accelerate faster.

http://www.physics.bc.edu/educational_resources/demos/data/RollingRace/MR7.html

 

http://www.sfu.ca/phys/233/labscripts/expt10.pdf

2 cars of identical overall mass are in a race on a straight track.

 

Car A has 10% of it's mass in the body and 90% of it's mass in the wheels (hypothetically)

 

Car B has 90% of it's mass in the body and 10% of it's mass in the wheels (hypothetically)

 

Which car will win assuming they both have the same power and are driven identically etc. ?

 

I think car B would win (but am not certain).

 

My answer without reading the thread:

 

B will win. A has greater rotational inertia to overcome and will spend energy doing that rather than translational motion. Assuming wheels same shape.

 

(Except car A must have yogurt pots with the lids sliding up and down for pistons and a papier-mache layshaft :rofl: )

the consencus here at work is that B would win - so I was right :hyper: :hyper: :bow:

 

this means that using lightweight alloys has a 2-fold benefit - reduced mass of overall car AND greater mechanical efficiency :duffer: ;)

 

I thought that was where you were going...

 

... and I was thinking of posting on this myself - I'm not too bothered about the look of alloys so I was thinking of finding out some masses.

 

But... a deep-dish alloy will have more rotational inertia than a simple spoked design of the same mass.

 

And in a real race (ie wiv sum corners) where does sprung v unsprung weight come into it?

Good work Nelson! You're one seriously obsessed guy!

 

New question. If car A has a low MASS collection of small dog clutch engaged gears attached to it and car B has heavy lumps of metal churning a puddle of ATF, which one would be the faster...

 

I'll get my coat.

 

:rofl: :rofl: :rofl:

B wins

 

Better sprung mass : unsprung mass ratio.

 

Therefore wheels easier to turn and grip the road better.

 

Probably.