Give the change in internal energy of a system if(a) W = 50 J, Q = 50 J; (b) W = -50 J, Q = -50 J; or (c) W = 50 J,Q = -50

A steam engine takes heat from steam at 221 °C to do work. If the surrounding air at 25 °C is treated as the cold reservoir and the power of the engine is 3.50x 103 hp, find (a) the maximum efficiency that the engine can have and (b) the minimum amount of heat discharged in the air each hour of running the engine. (а) |39.7 %; (b) 0.94 X x 1010 J.

A small civilian aircraft gasoline engine in an airplane, operating at 2.35 x 10³ rev/min, takes in energy 7.85 x 10³ J and exhausts 4.60 x 10³ J for each revolution of the crankshaft. (a) How many liters of fuel does it consume in 1.00 h of operation if the heat of combustion of the fuel is equal to 4.03 x 107 J/L? L/h (b) What is the mechanical power output of the engine? Ignore friction and express the answer in horsepower. hp (c) What is the torque (in N-m) exerted by the crankshaft on the load? N•m (d) What power (in W) must the exhaust and cooling system transfer out of the engine? W

If I add 11664 J of energy to an ideal gas inside a balloon, causing the internal energy to increase by 7278 J, how much work is done on the environment by the gas as the balloon expands?