# CBSE Worksheet for chapter-7 Fluid class 9

## Find CBSE Worksheet for chapter-7 Fluid class 9

CLASS-9

BOARD: CBSE

Physics Worksheet - 7

TOPIC: Fluid

For other CBSE Worksheet for class 9 Science check out main page of Physics Wallah.

#### SUMMARY

• Fluids,Pressure in fluids, Thrust, Units of pressure
• Buoyancy force, Factors affecting buoyant force
• Archimedes principle, Relative density, Uses of Archimedes principle
• Physical meaning of relative density, Law of floatation

#### SECTION I – OBJECTIVE

1. If a force of 10 N acts perpendicularly on two surfaces (area in the ratio 1:2), then the ratio of thrust will be:
1. 1:2
2. 2:1
3. 3:1
4. 1:1
2. A force of 50 N is applied normally on a nail of area 0.001 sq.cm. Then the thrust is:
1. 50 N
2. 100 N
3. 0.05 N
4. 10 N
3. Pressure cannot be measured in:
1. N/m2
2. bar
3. Pa
4. kg.wt
4. Pressure is:
1. Scalar quantity.
2. Normal force
3. Vector quantity
4. All the above are wrong
5. The atmosphere exerts a pressure of P on the surface of the earth, then P equals to:
1. 1.01x105 N/m2
2. 1.01x10-5 N/m2
3. 1.01x107 N/m2
4. 1.01x10-7 N/m2
6. Unit of relative density is:
1. kg/m3
2. g/m3
3. g/litre
4. Unit less
7. A cylinder of wood floats vertically in water with one-fourth of its length out of water The density of wood is:
1. 0.25 g/cm3
2. 0.5 g/cm3
3. 0.75 g/cm3
4. 1 g/cm3
8. Two solids X and Y float on water, X floats with half of its volume submerged while Y floats with one-third of its volume out of water. The densities of X and Y are in the ratio of:
1. 4:3
2. 3:4
3. 2:3
4. 1:3
9. Archimedes principle is used to:
1. Design ships
2. Design Submarines
3. Design Lactometers
4. All of them
10. As we move upwards, the atmospheric pressure:
1. Increases
2. Decreases
3. Remains same
4. cannot be said

#### SECTION II - SUBJECTIVE

1. Explain following terms:
1. Fluid
2. Pressure in fluid
3. Thrust
2. State Archimedes principle.
3. What is the pressure due to man weighing 80 kg, standing on his feet? Area of his feet= 160 sq cm.
4. (g = 10 m/s2)
5. What is height of mercury which exerts the same pressure as 20 cm of water column?
6. Take density of mercury as 13.6 g/cc.
7. When an aluminium object is immersed in water, it displaces 5 kg of water.
8. How much is the buoyant force acting on the aluminium object in newtons? (g= 10 m/s2)
9. The relative density of silver is 10.5. The density of water is 103 kg/m3. What is the density of silver in S.I. unit?
10. A body of volume 300 cm3 and relative density 1/3 is placed in water. Will it sink or float in water and what will be the volume of water displaced by it?.

### Solutions: to worksheet-7 Fluid

#### Objective Problems:

 1.(D) 2.(A) 3.(D) 4.(A) 5.(A) 6.(D) 7.(C) 8.(B) 9.(D) 10.(B)

#### Subjective Problems :

1. 5x104 N/m2
2. 1.48 cm.
3. 50 N
4. dAg = 10.5x103 kg/m3
5. Float, Volume = 100cm3