The weight of an empty balloon on a spring balance is W1. The weight b

1.	The weight of an empty balloon on a spring balance is W1. The weight becomes W2 when the balloon is filled with air. Let the weight of the air itself be w. Neglect the thickness of the balloon when it is filled with air. Also neglect the difference in the densities of air inside and outside the balloon. (a) W2 = W1. (b) W2 = W1 + w. (c) W2 < W1 + w. (d) W2 > W1.
Answer» (a) W₂ = W₁. (c) W₂ < W₁+ W. EXPLANATION: The weight of the empty balloon is W₁. The weight of the balloon filled with air should be W₁+w but the balloon is immersed fully in the air, so a force of buoyancy must act on it so the apparent weight W₂ < W₁+w, hence (c) is correct. Since the densities of air inside and outside are same so the weight of the displaced air by the balloon will also be w. Thus the apparent weight of air-filled balloon W₂ = (W₁+w)-w = W₁. Hence (a) is correct. Other options are not true.

The weight of an empty balloon on a spring balance is W1. The weight becomes W2 when the balloon is filled with air. Let the weight of the air itself be w. Neglect the thickness of the balloon when it is filled with air. Also neglect the difference in the densities of air inside and outside the balloon. (a) W2 = W1. (b) W2 = W1 + w. (c) W2 < W1 + w. (d) W2 > W1.

Answer»

(a) W₂ = W₁.

(c) W₂ < W₁+ W.

EXPLANATION:

The weight of the empty balloon is W₁. The weight of the balloon filled with air should be W₁+w but the balloon is immersed fully in the air, so a force of buoyancy must act on it so the apparent weight W₂ < W₁+w, hence (c) is correct. Since the densities of air inside and outside are same so the weight of the displaced air by the balloon will also be w. Thus the apparent weight of air-filled balloon W₂ = (W₁+w)-w = W₁. Hence (a) is correct. Other options are not true.

Discussion

No Comment Found

Related InterviewSolutions

A barometer kept in an elevator reads 76 cm when it is at rest. If the elevator goes up with increasing speed,the reading will be (a) zero(b) 76 cm(c) < 76 cm(d) > 76 cm.
A barometer kept in an elevator reads 76cm when it is at rest. If the elevator goes up with increasing speed, the reading will be(a) zero (b) 76cm (c) < 76cm (d) > 76cm.
A barometer kept in an elevator accelerating upward reads 76cm. The air pressure in the elevator is(a) 76cm (b) < 76cm (c) > 76cm (d) zero.
A piece of wood is floating in water kept in a bottle. The bottle is connected to an air pump. Neglect the compressibility of water. When more air is pushed into the bottle from the pump, the piece of wood will float with(a) larger part in the water(b) lesser part in the water(c) same part in the water(d) it will sink.
The weight of an empty balloon on a spring balance is W1. The weight becomes W2 when the balloon is filled with air. Let the weight of the air itself be w. Neglect the thickness of the balloon when it is filled with air. Also neglect the difference in the densities of air inside and outside the balloon. (a) W2 = W1. (b) W2 = W1 + w. (c) W2 < W1 + w. (d) W2 > W1.
Water is slightly coming out from a vertical pipe. As the water descends after coming out, its area of cross section reduces. Explain this on the basis of the equation of continuity.
A wooden object floats in water kept in a beaker. The object is near a side of the beaker (figure 13-Q4). Let P1, P2, P3 be the pressures at the three points A, B and C of the bottom as shown in the figure.(a) P1 = P2 = P3.(b) P1< P2 < P3.(c)P1 > P2 > P3.(d) P2 = P3 ≠ P1.
Equal mass of three liquids are kept in three identical cylindrical vessels A, B and C. The densities are PA, PB, PC with pA < pB < pC. The force on the base will be (a) maximum in vessel A (b) maximum in vessel B (c) maximum in vessel C (d) equal in all the vessels.
Equal mass of three liquids are kept in three identical cylindrical vessels A, B and C. The densities are pA, pB, pc with pA< pB< pC .The force on the base will be(a) maximum in vessel A(b) maximum in vessel B(c) maximum in vessel C(d) equal in all the vessels.
In a streamline flow,(a) the speed of a particle always remains same(b) the velocity of a particle always remains same(c) the kinetic energies of all the particles arriving at a given point are the same(d) the momenta of all the particles arriving at a given point are the same.

Discussion

No Comment Found

Related InterviewSolutions

Reply to Comment