The car is going at roughly the same speed as the truck, plus it has some
steep ramps to get up. Ideally the car is going just fast enough so it
barely has enough extra speed to roll up the ramps and into the truck when
the driver takes his foot off the gas. If the driver hits the ramps
faster, he may have to tromp on the breaks.
I'm ignoring the wheels. They'll chirp a little when they hit the ramp,
but unless they're under power that won't have much effect.
--
Stay alert! Trust no one! Keep your laser handy! The Computer is
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Note that very little speed has to be "absorbed" by the semi, since
the relative speed is quite small. Also note that the power output
of the car's engine at the time it reaches the ramp is quite small,
since it is drafting the truck/ramp and feeling less drag than at
that speed (so engine power is probably less than 10 hp). The KE
in the wheels is negligible.
As originally posed here, with a 5 mph difference in speed, the
car will not make it up the ramp. Good exercise to work out.
Estimate the KE in the wheels relative to that of the car, both
in the "truck frame" coordinate system.
>lets assume that the car is
>placed in neutral once it got up the ramps and into the trailer. what is
>the verdict? romp on the brakes or tap them!!!!
Whichever. It takes almost nothing to stop a car going a few mph.
An automatic won't even have to be put in neutral.
--
James A. Carr <j...@scri.fsu.edu> | Commercial e-mail is _NOT_
http://www.scri.fsu.edu/~jac/ | desired to this or any address
Supercomputer Computations Res. Inst. | that resolves to my account
Florida State, Tallahassee FL 32306 | for any reason at any time.