A village maintains a large tank with an open top, containing water for emergencies. The water can drain from the tank through a hose of diameter 6.60 cm. The hose ends with a nozzle of diameter 2.20 cm. A rubber stopper is inserted into the nozzle. The water level in the tank is kept 7.50 m above the nozzle. (a) Calculate the friction force exerted on the stopper by the nozzle. (b) The stopper is removed. What mass of water flows from the nozzle in 2.00 h

(A) Frictional force will be equal to 27.92 N

(B) Mass is equal to 33120 kg

Explanation:

(A) Diameter of nozzle d = 2.20 cm

So radius

eight h = 7.5 m

Density of water

Acceleration due to gravity

Pressure on the rubber stopper

Area of cross section

So force

(B) Speed of the water through nozzle

Volume of water flow

Mass of water flow per sec

Total time t = 2 hour = 2×3600 = 7200 sec

So total mass flow

number of electrons for neutral cl

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form