94. Amtrak\'s high speed train, the Acela, utilizes tilt of the carswhen negotia

Question

94.

Amtrak's high speed train, the Acela, utilizes tilt of the carswhen negotiating curves. The angle of tilt is adjusted so that themain force exerted on the passengers, to provide the centripetalacceleration, is the normal force. The passengers experience lessfriction force against the seat, thus feeling more comfortable.Consider an Acela train that rounds a curve with a radius of600 m at a speed of 180 km/h (approximately 113mi/h).

(a) Calculate the friction force needed on a train passenger ofmass 75 kg if the track is not banked and the train does nottilt.
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(b) Calculate the friction force on the passenger if the traintilts to its maximum tilt of 8° toward the center of thecurve.

Okay, so for part A, I found the frictional force to be 312.5 N, bylooking at the x component, using the equation Ffr =mv2/R. But I really don't understand how to get thefrictional force of B, without knowing s ork. I drew a FBD and I found that the forces in thex direction is Fnsin = mv2/R. And thatthe forces in the y direction is Fncos = 0,because it is not falling through the tracks. But where do I gofrom here? Am I even on the right track?
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Explanation / Answer

given radiusR = 600m        speed = 180km/h =180*5/18 = 50m/s mass of passenger = 75kg    maximum tlit = 80    if there is no tlit , then the frictionforce must supply the entire centripetal force on thepassenger      FR =mv2/R   plug values   F = ------N Ffricational = m(v2/r cos -gsin) plug values and do caliculations Ffr =-------N    if there is no tlit , then the frictionforce must supply the entire centripetal force on thepassenger      FR =mv2/R   plug values   F = ------N Ffricational = m(v2/r cos -gsin) plug values and do caliculations Ffr =-------N

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