Homework Help: Physics-energy

Posted by Anonymous on Tuesday, February 16, 2010 at 6:36pm.

Calculate the thermal energy dissipated from brakes in a 1310-kg car that descends a 13.5° hill. The car begins braking when its speed is 88 km/h and slows down to a speed of 34 km/h in a distance of 0.52 km measured along the road.

Physics-energy - bobpursley, Tuesday, February 16, 2010 at 6:43pm
thermal energy dissipated= change in KE+change in PE

= 1/2 m(vi^2-vf^2)+mg520*sin13.5

check my thinking.
Physics-energy - Damon, Tuesday, February 16, 2010 at 6:47pm
work done = force * distance

F = m a

Change in potential energy = - m g (.52*10^3) sin 13.5

Change in kinetic energy = - (1/2) m (88-34)^2 (10^3 m/km/3600s/hr)^2

thermal energy + change in potential energy + change in kinetic energy = 0

Answer this Question

Related Questions

physics - Proper design of automobile braking systems must account for heat ...
physics - Proper design of automobile braking systems must account for heat ...
Physics - The 2500 kg cable car shown in the figure below descends a 200 m high ...
science - a car of mass 1360 kg descends from a hill of height 86 m at a ...
Physics - A 2.0 x 103 kg car is pulled 345 m up a hill that make s an angle of ...
Physics - A 2.0 x 103 kg car is pulled 345 m up a hill that make s an angle of ...
Physics - A 2.0 x 103 kg car is pulled 345 m up a hill that make s an angle of ...
Thermal Physics - Two cars collide head on while each is travelling at 80 km/hr...
physics-energy conservation - when you apply the brakes of a car its kinetic ...
physics - A car with a mass of 890 kg travels at a speed of 20.0 m/s. Seeing ...

For Further Reading

First Name:
School Subject:
Answer: