In: Physics
Derive an expression for the power going into the braking system when a car is decelerated from a speed u to a standstill with constant deceleration a (Remember using v = u-at = 0, where a is the magnitude of the deceleration) on a level road. Include the force required to overcome aerodynamic drag (1 ??2???) and rolling 2 friction (μmg). (2) Hence, derive an expression to allow the energy dissipated during the deceleration period to be calculated. (3) The car has a total, fully loaded, mass of 1050 kg. The requirements state that the car must be able to brake from a speed of 100 km/h to a standstill on a level road within one minute. The rolling coefficient of friction of the tyres is 0.02 and the drag coefficient is 0.8. The frontal area of the car is 1.9 m2 and the density of air is 1.2 kg/m3. Calculate the energy dissipated from the engine for the car to brake under constant deceleration and the other given conditions.