Mechanical Properties of Fluids — Physics STD 11 Science — Question

Ravi came to stay in a multistoried building. He noticed that motor supplying water to the second floor is power rating X k W while of that supplying water to 8^th floor is Y k W. He asked his father the reason behind the difference of the power ratings. His father explained him the reason.

1. What values does Ravi posses?
2. Which power rating is more X or Y?
3. A motor pumps up 1000kg of water through a height of 10min 5 s. If the efficiency of the motor is 60%, calculate the power of the motor in kilowatt. 

What is common between the two graphs shown in Figs. (a) and (b)?

What should be the maximum average velocity of water in a tube of diameter 2cm so that flow is laminar? The viscosity of water is 0.001Nm^-2s.

From the given example, find if the motion is one or two or three-dimensional.

1. A kite flying in the sky.
2. A cricket ball hit by a player.
3. Moon revolving around the earth.
4. The motion of a stone in a circle.

Write the number of significant digits in:

1. 1001
2. 100.1
3. 100.10
4. 0.001001

Calculate the number of atoms in 39.4g gold. Molar mass of gold is 197g mole^–1.

In a coal fire, the pockets formed by coals appear brighter than the coals themselves. Is the temperature of such a pocket higher than the surface temperature of a glowing coal?

Calculate the power of a crane in watts, which lifts a mass of 100kg to a height of 10 m in 20s.

Calculate the momentum of a photon of light of wavelength 500nm.