Truck brakes used to control speed on a downhill run do work, translating gravitational potential energy into increased internal energy (higher temperature) of the brake material. This translation prevents the gravitational potential energy from being converted into kinetic energy of the truck. However, the mass of the truck is large compared with that of the brake material absorbing the energy, and the temperature increase may occur too quick for enough heat to transfer from the brakes to the environment. Assume the mass of truck is 8,000 kg. Calculate the temperature increase of 95 kg of brake material with an average specific the heat of 800 J/kg ⋅ ºC if the material retains 10% of the energy from a truck descending 75.0 m (in vertical displacement) at a constant speed.
Truck brakes used to control speed on a downhill run do work, translating
gravitational potential energy into increased internal energy (higher temperature) of the brake material. This translation prevents the gravitational potential energy from being converted into kinetic energy of the truck. However, the mass of the truck is large compared with that of the brake material absorbing the energy, and the temperature increase may occur too quick for enough
environment. Assume the mass of truck is 8,000 kg.
Calculate the temperature increase of 95 kg of brake material with an average specific the heat of 800 J/kg ⋅ ºC if the material retains 10% of the energy from a truck descending 75.0 m (in vertical displacement) at a constant speed.
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