Aswimmer wants to swim straight across a river with current flowing at a speed of v1 = 0.32 km/h. if the swimmer swims in still water with speed v2 = 0.85 km/h, at what angle θ should the swimmer point upstream from the shore and at what speed v will the swimmer swim across the river?

The difference between two numbers is 15. when twice the smaller number is subtracted from three times the larger number, the difference is 58.what is the larger number?

Acoal-fired plant generates 600 mw of electric power. the plant uses 4.8 x 10^6 kg of coal each day, and the heat of combustion of coal is 3.3x 10^7 j/kg. the steam that drives the turbines is at a temperature of 300° c, and the exhaust water is at 37° c. (a) what is the overall efficiency of the plant for generating electric power? (b) how much thermal energy is exhausted each day? (c) what is the change in entropy of the universe for this heat engine? (d) using the same heat reservoirs, what is the maximum possible (carnot) efficiency for a heat engine?

A248-g piece of copper is dropped into 390 ml of water at 22.6 °c. the final temperature of the water was measured as 39.9 °c. calculate the initial temperature of the piece of copper. assume that all heat transfer occurs between the copper and the water. remember, the density of water is 1.0 g/m