energy

a 90g bullet is fired from a rifle having a barrel 0.690m long. Assuming the origin is placed the bullet begins to move , the force (in newtons) exerted on the bullet bu the expanding gas is 1000 + 6000x- 35000x*x where x is in meteres a) determine the work done by the gas on the bullet as the bullet travels the length of the barrel (in kJ) b) if the barrel is 1.15m long, how much work is done and how does this value compare to the work calculated in part(a)_____kJ _______(work done with 1.15m barrel/work done with te 0.690m barrel)

tension and work

A sledge loaded with bricks has a total mass of 18.0 kg and is pulled at constant speed by a rope. The rope is inclined at 20.0° above the horizontal, and the sledge moves a distance of 20.0 m on a horizontal surface. The coefficient of kinetic friction between the sledge and surface is 0.550. (a) What is the tension in the rope? N (b) How much work is done on the sledge by the rope? J (c) What is the increase in internal energy in the sledge and the surface due to friction? J

Thermodynamics: ice water

An ice cube weighs 30 grams at 0 degrees Celsius. It is added to 200 g of water at 80 degrees Celsius in an insulated container. What is the final temperature of the mixture? The affect of the container is negligible.

Thermodynamics: Heated rod

At 6 degrees Celsius a metal rod is 1.5 m total length with half the length steel and the other half brass. The rod is heated to 150 degrees Celsius. What is the total change in length?

Thermodynamics: Heat engine

A heat engine has an energy source of 500 degrees Celsius, and it has a cooling system at 90 degrees Celsius. What is the maximum efficiency possible of this engine? If the engine does 100 kJ of work what is the least amount of heat it must exhaust?