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# Physics word problem help please?

Topic: Problem solving four steps to
July 18, 2019 / By Jordon
Question: When a driver brakes an automobile, friction between the brake disks and the brake pads converts part of the car's translational kinetic energy to internal energy. If a 1360 kg automobile traveling at 36.4 m/s comes to a halt after its brakes are applied, how much can the temperature rise in each of the four 3.5 kg steel brake disks? Assume the disks are made of iron (cp = 448 J/kg·°C) and that all of the kinetic energy is distributed in equal parts to the internal energy of the brakes. ____ °C rise in temperature

Georgene | 7 days ago
Amount of energy to be dissipated by the brakes: K.E. = 1/2 * m * v^2 = 1/2 * 1360 * 36.4^2 = 900973 Joules Amount of energy for each brake: 900973 / 4 = 225243 Joules (rounding off to nearest '1') 225243J / (3.5 kg * 448 J / kg*degreeC ) = 144 degree C rise. This last step is solved by simply taking the information in the problem and figuring out how to cancel out dimensions (J/J and kg/kg) until you are left with degreesC, only. .
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