Physics is awesome

[krash]

A couple of weeks ago in my physics 1 class we were going over turning on banked curves with friction. Say a car goes around a banked curve. When you're doing the math, the mass of the car divides out, meaning that the mass of the car is irrelevant to the speed it can go around a curve. Obviously in a more complicated physics class they'll factor in center of gravity, but still, I thought this was AWESOME.

[alms24sebring]

yeah we did this too. I didnt know the mass didnt matter tho. I thought it was center of gravity or mass, angle, velocity, and the coeff of friction that mattered. Where you trying to find the breaking point of the tires?

[krash]

Yea we were finding the fastest velocity that the tires can hold without slipping. The mass divides out at this level of physics, but later on center of mass will definitely play a role.

Imagine a dump truck flying around a curve at the same max velocity as a miata

[bigbadberry3]

Yes. Yes it is. (High school physics teacher )

[Looneybomber]

My physics teacher taught us all kinds of weird non-physics things, but with a physics twist. He would use the theory of relativity and newtons laws to explain human behaviors and relationships...

I forget who said the speed of light is faster than the speed of sound, which is why some people appear bright until you hear them speak.

[szh]

A couple of weeks ago in my physics 1 class we were going over turning on banked curves with friction. Say a car goes around a banked curve. When you're doing the math, the mass of the car divides out, meaning that the mass of the car is irrelevant to the speed it can go around a curve. Obviously in a more complicated physics class they'll factor in center of gravity, but still, I thought this was AWESOME.

I assume you are talking about the lateral acceleration formula being "radius times omega squared" or the equivalent "velocity squared divided by radius", right?

Z

[alms24sebring]

probably the v^2/r. Isnt there a sin/cos theta in there somewhere?

[szh]

probably the v^2/r. Isnt there a sin/cos theta in there somewhere?

In a banked turn, yes.

Sorry, I confused things slightly ... I was talking about lateral acceleration on a non-banked turn. Where the following equation holds (sorry for the geek factor, but this is a Science forum after all! )

u*m*g=m*(v^2/r) at the point of slipping.

And, m cancels out ... as noted by the OP.

By the way, lateral acceleration is simply (v^2/r) and it is simply F = ma that leads to the m*(v^2/r) above.

Of course, as I recall (my physics is rusty now), mass also cancels out when it is calculated on a banked turn ... either with or without friction.

Z

[alms24sebring]

Thanks, I knew it was something like that I just dont recall. I dont even know if I can find that notebook with that in it although I am very curious now.