# ICSE Worksheet for chapter-8 Up thrust in Fluids and Archimedes class 9

## Find ICSE Worksheet for chapter-8 Up thrust in Fluids and Archimedes class 9

CLASS-9

BOARD: ICSE

Physics Worksheet - 8

TOPIC: Up thrust in Fluids and Archimedes

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

#### SUMMARY

• Buoyancy And Upthrust

• Characteristics And Properties Of Up Thrust

• Reasons For Upthrust

• Upthrust Is Equal To The Weight Of The Liquid Displaced

• Archimedes Principle

#### SECTION 1 – OBJECTIVE

1. Two balls, one of iron and other of aluminium experience same up thrust when dipped in water if:

(A) Both have equal volume

(B) Both have equal weight in air

(C) Both have equal density

(D) Nothing definite can be said

2. An empty tin container with its mouth closed has an average density equal to that of liquid A.

The container is taken 2 m below the surface of liquid A and is left there. Then:

(A) Container will bounce back to the surface.

(B) Container remains where it is left.

(C) Container sinks further.

(D) Nothing can be said.

3. A piece of wood is held under water. The upthrust on it will be:

(A) Equal to the weight of wood piece. (B) Less than the weight of wood piece.

(C) More than the weight of wood piece.

(D) Zero.

4. The upthrust experienced by a body immersed in a liquid is equal to:

(A) The weight of body itself

(B) The volume of a liquid displaced by the body

(C) The volume of the body itself

(D) The weight of the liquid displaced by the body

5. Any solid will experience minimum upthrust when it is immersed in:

(A) 0 : 1

(B) Water

(C) Seawater

(D) Mercury

6. A body of density ρ sinks in a liquid of density ρL. The densities ρ and ρL are related as:

(A) ρ = ρL

(B) ρ < ρL

(C) ρ > ρL

(D) Nothing can be said.

7. The S.I. unit of upthrust is:

(A) Pa

(B) N

(C) kg

(D) kg m2

8. A piece of 100 n is held under water. The upthrust on it will be…. the weight of the wood piece.

(A) Less than

(B) More than

(C) Same as

(D) Less or more

9. A body of volume 100 cm3 weighs 5 kgf in air. It is completely immersed in a liquid of density

1.8x103 kg m-3. Find the upthrust due to liquid.

(A) 0.18 kgf

(B) 0.28 kgf

(C) 1.8 kgf

(D) 0.12 kgf

10. Unit of density is:

(A) kg-m/s

(B) N-m

(C) J/s

(D) None of these

#### SECTION 2 – SUBJECTIVE

1. Define upthrust, what is the cause of upthrust? State its S.I. unit.

2. State Archimedes’ principle.

3. An iron nail floats on mercury but it sinks in water. Explain the reason.

4. Describe an experiment based on Archimedes’ principle to find the relative density of a liquid.

5. A body of mass 3.5 kg displaces 1000 cm3 of water when fully immersed inside it. Calculate

(i) The volume of body (ii) The upthrust on body (iii) The apparent weight of body in water.

6. A metal cube of 5 cm edge and density 9 g cm-3 is suspended by a thread so as to be completely immersed in a liquid of density 1.2 g cm-3. Find the tension in thread. (Take g = 10 m s-2).

7. A sphere of iron and another of wood of same radius are held under water. Compare the upthrust on the two spheres.

### Solutions: to worksheet-8 Topic-Up thrust in Fluids and Archimedes

#### objective problem

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

#### SUBJECTIVE PROBLEM

5. (i) 1000cm3

(ii) 1 Kgf

(iii) 2.5 Kgf

6. Tension in the thread = 9.75N