Give reason for the following: a) An inflated balloon was pressed against a wall after it has been rubbed with a
piece of synthetic cloth. It was found that the balloon sticks to the wall.
b) When an object is thrown up, it comes back to ground.
c) Mountaineers suffer nose bleeding at higher altitudes.
d) Foundations of high rise buildings are kept wide.
e) Deep sea divers or high altitude fliers wear special suits.
f) Walls of a dam are thickened near the base.

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?

Asher cycles 12 miles in 16 hours. what is his speed?

Aperson walks first at a constant speed of 4.89 m/s along a straight line from point a to point b and then back along the line from b to a at a constant speed of 2.95 m/s. what is the average speed over the entire trip?