i was working on a word problem for calculus and it had to do with the movement of pistons in a car. i thought it was really interesting. it basically explains how much forces increase on moving parts as you increase the speed of the motor.

for those of you that care, the formula is s=A*cos(2*Pi*b*t)
where A is amplitude of motion, b is frequency (# of times the piston moves up and down each second), and t is time in secs.

anyways, i found out the following:

if we double the frequency (rpm), that causes the velocity to double (which isnt very impressive...)

if we double the frequency (rpm), that causes the acceleration of the piston to quadruple. (thats fast...)

if we double the frequency (rpm), that causes the jerk (the stress caused by the piston changing direction rapidly) to be multiplied by a factor of 8 (ouch!)

i felt it kind of put things into perspective. at the very least, it made my class interesting for once. maybe you'll think twice before going to the redline next time

 

You want a really good calculus problem, calculate the piston speed as a function of crank RPM.

 

ill give anyone the answer if you pay me 10 bucks. hah.

 

then calculate the amount of stretch iron rods see at rev limiter.

then calculate for Titanium.

think about how you can make more power

Interesting!


[Modified by lazerus, 8:09 PM 2/27/2003]

 

same thing for air drag. double the speed, quadruple the drag force of the air. its all due to the low pressure behind your car. whats you major??? Mechanical engineer???? well it should be!!!
later

 

how about taking the force my''=mg-cy'. And then start by taking the triple integral of e^x. hahaha. i love math. its one of those things that is just great.

 

RPM=Ruins People's Motors
Never made it past trig...

 

I made it halfway through calc. in HS, then dropped it. I then tested into a math class for college that is equivalent to what I took my freshman year...go figure.
college blows, I dont think Im going back....