A steam engine delivers `5.4 xx 10^8J` of work per minute and services `3.6 xx 10^9J` of heat per minute from its boiler. What is the efficiency of the engine? flow much heat is wasted per minute?

A person trying to lose weight (dieter) lifts a 10 kg mass, one thousand times, to a height of 0.5 m each time. Assume that the potential energy lost each time she lowers the massis dissipated:- Fat supplies 3.8 xx 10^7J of energy per kilogram which is converted to mechanical energy with a 20% efficiency rate. How much fat will the dieter use up?

A man would be 5 minutes late to reach his destination if he rides his bike at 30 km per hour.But he would be 10 minutes early if he rides at the speed of 40 km per hour.What is the distance of his destination from where he starts?

A geyser heats water flowing at the rate of 3.0 litres per minute from 27 ^@C to 77 ^@C . If the geyser operates on a gas burner, what is the rate of consumption of the fuel if its heat of combustion is 4.0 xx 10^4 J//g ?

The rate constant of the reaction A rarr B is 0.6 xx10^-3 mole per second. If the concentration of A is 5 M, then concentration of B after 20 minutes is:

The length 'x' of a rectangle is decreasing at the rate of 5 cm per minute and the width 'y' is increasing at the rate of 4 cm per minute, when x = 8 cm and y = 6 cm, find the rate of change of the area of the rectangle.

The length 'x' of a rectangle is decreasing at the rate of 5 cm per minute and the width 'y' is increasing at the rate of 4 cm per minute, when x = 8 cm and y = 6 cm, find the rate of change of the perimeter of the rectangle.

The side of a square sheet is increasing at 3 cm per minute. At what rate is the area increasing when the side is 10 cm long?