The Physics Behind Parking :: physics science cars vehicles

Background aft(prenominal) a long day of cruising through town with your buddy, the dickens of you take hold grown quite an appetite. You spot a McDonalds at the top of a very steep hill. Unfornately a local biker gang essential of had the equal idea. Encredibly, the only available putting surfaceing spot is on the street, uphill of closely 15 Harleys. There are no other restaurants for 100 miles in all directions. Famished, your friend skillfully manuvers his car to the side of the road. The breaks shudder as the car comes to a stop on the hill. He holds the brake, puts it into first, and shuts attain the car. botherBikers dont take kindly to people messing with their bikes. Your friend is about to let off of the brake. Being the physics major you are, you have to decide whether its safe to park or safer to go hungry. Your friends car is pretty old, and the e-brake hasnt worked for years. The car will be held in place solely by the moter. There are two mean looking bikers smo king outside entrance. They are honoring you so there probably wouldnt be time to make a run for it.Known What You KnowYour buddys car is classic, and Im sure he would essential to make more than an educated guess. Ive done a little analyze to help you out a bit. I took a torque rack to the motor, and resists it resists aproximately 46 ft*lbs of torque at the crankshaft. After the compression bleeds graduate this number is reduced to 38 ft*lbs. The cars rear differential has a 3.73 to 1 gear ratio and a manual transmission with a 3.35 to 1 ratio in first gear. The tires are 28 inches in diameter and the gross weight of the car is approximately 2100 lbs. The hill is frequently travelled by truckers, and on the way up you noticed a sign that said the hill was at a 26 grade angle with the horizontal. SummaryWhen the car is at rest this means it is in a system of static equilibrium. Gravity is pushing forward on the car, and the tires are pushing back on the car via the reaction throw of friction in the motor. The steeper the hill, the greater the force of gravity acting on the car, the greater the reaction force in the motor must have. As stated before, the maximum torque that can be utilize to the motor before it rotates is 38 ft*lbs.