FR-S vs Lexus RC-F

[ST185RC]

Originally Posted by richardM

Sorry.. force= mass times acceleration
The heavier car has more force, so if both have equal resistance, the heavier car will fall faster.

Think of it this way.. the heavier car took more energy to pull it high in to the sky, and that energy is used to overcome the air resistance on the way back down hill.

When in doubt, try an experiment: get two toy balloons. Fill one with air and the other with water. Make them the same size so they have the same air resistance. Drop them both at the same time and see which hits the ground first.

A piece of paper and book have the same cross sectional area. Drop them side by side. CLEARLY the book falls faster.

So.. theory and experiment confirm.. Newton's laws work.

You need to to go back to physics 11. Kinematics > you. For two free falling bodies dropped at the same height (that is, no external impulse) acceleration would be earth's constant force of gravity, both would reach the ground at the same time in a vacuum; the force of impact would be different due to mass, but acceleration is the same. The only thing affecting the free falling bodies (acceleration and terminal velocity) would be (in earth's atmosphere) air resistance and aero dynamics.

[powerj2]

apples and oranges

[chaoskaze]

Originally Posted by richardM

Sorry.. force= mass times acceleration
The heavier car has more force, so if both have equal resistance, the heavier car will fall faster.

Think of it this way.. the heavier car took more energy to pull it high in to the sky, and that energy is used to overcome the air resistance on the way back down hill.

When in doubt, try an experiment: get two toy balloons. Fill one with air and the other with water. Make them the same size so they have the same air resistance. Drop them both at the same time and see which hits the ground first.

A piece of paper and book have the same cross sectional area. Drop them side by side. CLEARLY the book falls faster.

So.. theory and experiment confirm.. Newton's laws work.

I hate to bring it to you but newton probably wanna punch u in the face........... cuz even he knows..........think gravity...

[HunterGreene]

Originally Posted by swarb

.29 cd vs .33 for the rcf, so we cut the air better, so technically we would crash first. Dunno who wins though, die first or stay alive longer?

Originally Posted by ScoobsMcGee

Wouldn't that mean the car would have to fall nose-first the entire time? Now we need to consider weight distribution and counter-balancing to ensure optimal cd while falling to a splattery demise.

Originally Posted by richardM

Sorry.. force= mass times acceleration
The heavier car has more force, so if both have equal resistance, the heavier car will fall faster.

Think of it this way.. the heavier car took more energy to pull it high in to the sky, and that energy is used to overcome the air resistance on the way back down hill.

When in doubt, try an experiment: get two toy balloons. Fill one with air and the other with water. Make them the same size so they have the same air resistance. Drop them both at the same time and see which hits the ground first.

A piece of paper and book have the same cross sectional area. Drop them side by side. CLEARLY the book falls faster.

So.. theory and experiment confirm.. Newton's laws work.

Originally Posted by chaoskaze

I hate to bring it to you but newton probably wanna punch u in the face........... cuz even he knows..........think gravity...

To get back in the realm of real-world physics...

Variables and how much they matter in a real-world, atmosphere test, where wind speed is assumed = 0, temperature is considered constant along the fall path, and both are dropped "flat" (aka wheels down).

Weight difference: Negligible, given drag coeff.
Drag coefficient: Negligible, as the weight dif. effectively cancels this out (don't feel like doing math)
Weight distribution: This is where it gets interesting, beause the Lexus is slightly more biased towards the front (55% front as opposed to FR-S at 53%). This means, given wind resistance, the Lexus will nose down slightly more, which means it is *slightly* more aerodynamic.

What will this translate to? Not much, but the Lexus may impact a fraction of a second sooner. Now, real world, you could do this test a bunch of times and you will likely get cases where the Lexus impacts first, then the FR-S hits first on the next test.

On second thought, just flip a quarter. You can do it more easily, it won't cost nearly as much, and you'll likely get the same set of results.

[richardM]

Sighs. You all do not want to to the math, and you do not want to do the experiments. We have air on this planet. That's how the airplane flew up to several thousand feet to drop the two cars.

Lets assume that the BRZ and the Lexus have the same shape and that both will be randomly tumbling objects so present the same aerodynamic cross section.

The mass is proportional to the weights: assume the BRZ weighs 2,800 lbs and the BRZ 3,800 pounds (it's a bit more, actually.) That puts the mass of the Lexus at about 30 percent more (conservatively) than the BRZ.

Here is a fun video that will help you understand.
1. They drop a pillow and a kitchen stove from 60 Meters.The pillow quickly reaches it's terminal velocity and the much bigger (more air resistance) kitchen stove hits the ground first.

2. Two identical balls, one made of steel. Identical aerodynamic shapes.. the heavier ball clearly hits first. You can see it. Both balls have the same retarding force do to the aerodynamics, but the steel ball's greater mass overcomes the air resistance.

3. Dropping a car and the truck tire help explain.. but we are dropping the cars from an airplane so I assume plenty of time for the cars to reach terminal velocity and that occur more quickly for the FRS as it's 30% less mass.

Before making a condescending reply, you might want to consider... we live in a complex world where things like friction, atmosphere and aerodynamics matter. I might be a stranger but I have considerable real world experience dropping things, flying things, rolling things down hill and teaching things.

This video is great, if only because they drop a car.

[ame="https://www.youtube.com/watch?v=AYz_K3mwq6A"]Brainiac - Do heavy objects fall faster than light objects ? Aristotle vs Galileo - YouTube[/ame]

Originally Posted by ST185RC

You need to to go back to physics 11. Kinematics > you. For two free falling bodies dropped at the same height (that is, no external impulse) acceleration would be earth's constant force of gravity, both would reach the ground at the same time in a vacuum; the force of impact would be different due to mass, but acceleration is the same. The only thing affecting the free falling bodies (acceleration and terminal velocity) would be (in earth's atmosphere) air resistance and aero dynamics.

[Tcoat]

Originally Posted by richardM

Sighs. You all do not want to to the math, and you do not want to do the experiments. We have air on this planet. That's how the airplane flew up to several thousand feet to drop the two cars.

Lets assume that the BRZ and the Lexus have the same shape and that both will be randomly tumbling objects so present the same aerodynamic cross section.

The mass is proportional to the weights: assume the BRZ weighs 2,800 lbs and the BRZ 3,800 pounds (it's a bit more, actually.) That puts the mass of the Lexus at about 30 percent more (conservatively) than the BRZ.

Here is a fun video that will help you understand.
1. They drop a pillow and a kitchen stove from 60 Meters.The pillow quickly reaches it's terminal velocity and the much bigger (more air resistance) kitchen stove hits the ground first.

2. Two identical balls, one made of steel. Identical aerodynamic shapes.. the heavier ball clearly hits first. You can see it. Both balls have the same retarding force do to the aerodynamics, but the steel ball's greater mass overcomes the air resistance.

3. Dropping a car and the truck tire help explain.. but we are dropping the cars from an airplane so I assume plenty of time for the cars to reach terminal velocity and that occur more quickly for the FRS as it's 30% less mass.

Before making a condescending reply, you might want to consider... we live in a complex world where things like friction, atmosphere and aerodynamics matter. I might be a stranger but I have considerable real world experience dropping things, flying things, rolling things down hill and teaching things.

This video is great, if only because they drop a car.

Holy crap you really believe it don't you!
Yes aerodynamics matter, yes air resistance changes the fall. But.... ahhh shit forget it I don't feel like beating my head against a wall! And god help anybody that you are "teaching"!!!
http://socratic.org/questions/how-do...alling-objects
http://www.physicsclassroom.com/clas...Air-Resistance

[babydriver]

Originally Posted by richardM

Sorry.. force= mass times acceleration
The heavier car has more force, so if both have equal resistance, the heavier car will fall faster.

The earth's mass is 5.97 × 10 F [ame="http://en.wikipedia.org/wiki/Kilogram"]Kilogram - Wikipedia, the free encyclopedia[/ame]. That's about 6 followed by 24 zeros. The mass of the Lexus is about 1800 kg and the mass of the FR-S is about 1225 kg. The earth and the car attract each other mutually (Newton's THIRD law of motion), but the acceleration of the cars toward the earth is insignificantly different from each other due to the overwhelmingly larger mass of the earth compare to the cars.

If there is a significant difference in air friction between the falling cars, then of course there will be some difference in the terminal velocity of the two vehicles. If it is not significant, then they will strike the ground simultaneously.

See this video of Apollo 15 proving this point on the moon. No air resistance so they hit the ground simultaneously.

[ame="https://www.youtube.com/watch?v=-4_rceVPVSY"]Apollo 15 Hammer and Feather Drop - YouTube[/ame]

F=MA but in this case the acceleration is virtually identical for both vehicles due to the earth's mass compared to the cars' mass.

[richardM]

Originally Posted by Tcoat

Holy crap you really believe it don't you!
Yes aerodynamics matter, yes air resistance changes the fall. But.... ahhh shit forget it!

Why do racing sailplanes fill their wings with water?
Why do racing gravity bikes have a ballast weight limit?
Why do heavy bike racers descend so much faster, side by side, than lighter bike racers? (it's obvious. Chubby guys like me rule downhill speed. Draft the heavy guys, bro.)
Why do heavy cargoes require bigger round parachutes for safe delivery?

Watch the video- you can even observe that in 60 meters the two objects are close. But watch MORE closely... they are not exactly hitting the same time/distance apart that they were dropped from. Redo at 1,000 feet?

Ok... so matchbox cars are 1:64 scale. Lets neglect reynolds numbers effects... I'll get two identical matchbox cars and load one internally with lead so it has 33% more mass. Once both cars reaches terminal velocity.. it doesn't how high we drop them from. I can get access to the roof of a 4 story building and we can use the Physics 1 electromagnet dohickey to drop them at exactly the same time. Now... who wants to put money on which little car hits first?
Watch the video.

Tcoat.. there is AIR on PLANET EARTH! We don't live in a Vacuum! We have air! We breathe it.. engines burn it, F1 cars use it.. all that stuff. We are not talking about in a vacuum. Eyeballs boil. Air resistance MATTERS. It's why we don't race Nissan cubes! The two cars will have different TERMINAL VELOCITIES.. the point where the force from moving the air out of the way balances the acceleration due to gravity. And it matters when you want to know which hits the ground first. I dare you.. Order two pizzas. Open the boxes. Take one pizza and put it with it's friend.. double pizza in one box, one box empty. Drop both boxes out of a 3 story window. You KNOW which will hit first. Because.. air. I know all about the acceleration of gravity matching the difference in inertia- but there as a term of air resistance that is linear in velocity compared to frontal impact of the object, proportional to v squared in friction along the sides, and mad crazy function with regards to slipstream turbulence. These aerodynamic FORCES retard the acceleration of the objects... and the lighter object comes to equilibrium more quickly that the heavy object providing they have the same shape.

Yeah, yeah.. you keep dropping stuff in a vacuum. That's not relevant to this discussion.. because, air.

[babydriver]

Originally Posted by richardM

Sorry.. force= mass times acceleration
The heavier car has more force, so if both have equal resistance, the heavier car will fall faster.

Think of it this way.. the heavier car took more energy to pull it high in to the sky, and that energy is used to overcome the air resistance on the way back down hill.

When in doubt, try an experiment: get two toy balloons. Fill one with air and the other with water. Make them the same size so they have the same air resistance. Drop them both at the same time and see which hits the ground first.

A piece of paper and book have the same cross sectional area. Drop them side by side. CLEARLY the book falls faster.

So.. theory and experiment confirm.. Newton's laws work.

Apparently you would have done well in the 17th century; also, the earth is flat. Do me a favor, Google Galileo and read about his experiment at the Tower of Pisa concerning falling weights.

[swarb]

mmmmm pizza

[REAV3R]

This thread is full of win.

[Tcoat]

Originally Posted by richardM

Why do racing sailplanes fill their wings with water?
Why do racing gravity bikes have a ballast weight limit?
Why do heavy bike racers descend so much faster, side by side, than lighter bike racers? (it's obvious. Chubby guys like me rule downhill speed. Draft the heavy guys, bro.)
Why do heavy cargoes require bigger round parachutes for safe delivery?

Watch the video- you can even observe that in 60 meters the two objects are close. But watch MORE closely... they are not exactly hitting the same time/distance apart that they were dropped from. Redo at 1,000 feet?

Ok... so matchbox cars are 1:64 scale. Lets neglect reynolds numbers effects... I'll get two identical matchbox cars and load one internally with lead so it has 33% more mass. Once both cars reaches terminal velocity.. it doesn't how high we drop them from. I can get access to the roof of a 4 story building and we can use the Physics 1 electromagnet dohickey to drop them at exactly the same time. Now... who wants to put money on which little car hits first?
Watch the video.

Tcoat.. there is AIR on PLANET EARTH! We don't live in a Vacuum! We have air! We breathe it.. engines burn it, F1 cars use it.. all that stuff. We are not talking about in a vacuum. Eyeballs boil. Air resistance MATTERS. It's why we don't race Nissan cubes!

I know that air resistance matters damn it! I said that.
Heavier objects do not fall faster because of mass PERIOD!
For crying out loud you said the pillow reached it's terminal velocity faster because it is lighter!!!!
I give up and please for the sake of humanity don't "teach things" ever again.

[kosoku]

this thread is awesome.

[Tcoat]

"but there as a term of air resistance that is linear in velocity compared to frontal impact of the object, proportional to v squared in friction along the sides, and mad crazy function with regards to slipstream turbulence."