Physics Multiple Choice Show your work , explanation to getting answer . It is m

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Physics Multiple Choice

Show your work , explanation to getting answer . It is multiple choice but i still require some work made so that I understand .Thank You

Please answer and comment as fast as possible , do not hesitate to ask me anything .

You bought a 1.5-kg "solid" gold paperweight for only 1000 baht. When lowered into a tank of water , it displaces 100 cm^3 of water. The density of gold iss 1.93 x 10 ^4 kg/m^3 .

A. You made a great purchase , the density is correct for solid gold. B. The density is too low,it is definitly not solid gold. C.The density is too high , it is definitely not solid gold. D. None of the above.

A block of wood floats in a pot of water on the floor of an elevator. Ignoring surface tension, how is the depth at which it floats changed when the elevator accelerates downward at a rate less thing? The block rises because the water sinks. The block lowers because the water rises. Nothing happens to it. The depth decreases because the water gets effectively lighter. None of these. In the fist tank above, it is possible that the pressure is equal at points A and B and E B and C and E A and C and E A and C and B there are no three points that could have equal pressure. Water traveling at a speed of 0.1 m/s enters a pipe with a 1.0-cm radius. It emerges them a section of pipe with a radius of 0.5-cm radius at a speed of 0.4 m/s 0.2 m/s 1.0 m/s 0.04 m/s None of these A milk container has two holes punched in its side, one at point 1.75 cm down from the liquid level, and the other at point 2, 15 cm down from that level. The exit speeds at point 1 and point 2 are related by v1 = v2 v2 = 2v3 v1 = 2v2 v3 = None of these

Explanation / Answer

1)mass of solid gold m = 1.5 kg

volume of water displaced is V = 100 cm^3 = 100 x 10^-6 m^3

the density of gold is p = 1.93 x 10^4 kg/m^3

we know that

p = m/V1

or V1 = m/p = (1.5/1.93 x 10^4) = 0.7772 x 10^-4 m^3 = 77.72 x 10^-6 m^3

here,V1 is volume of gold

Therefore,the density is correct for solid gold.

2)Nothing happens to it.

3)there are no three points that could have equal pressure.

4)here,v1 = 0.1 m/s and r1 = 1.0 cm = 1.0 x 10^-2 m

let v2 be the speed when r2 = 0.5 cm = 0.5 x 10^-2 m

we know that

A1 x v1 = A2 x v2

or v2 = (A1 x v1/A2) = v1 x (r1/r2)^2

5)the distance of the points from the origin are

r1 = (1^2 + 7.5^2)^1/2 x 10^-2 m

and r2 = (2^2 + 15^2)^1/2 x 10^-2 m

we know that

A1 x v1 = A2 x v2

or r1^2 x v1 = r2^2 x v2

or 57.25 x v1 = 229 x v2

or v1 = 4 x v2

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