All categories

3 years ago

Hello, I need help with a question

Physics

2 answers:

VikaD [51]3 years ago

8 0

Answer:

a. buoyancy

....................

Natasha2012 [34]3 years ago

4 0

Answer:

The Answer is (A) . . .

I Think . . .

You might be interested in

A circular copper wire is put in tension under a weight of 7000N. What is the ratio of its diameter after and before the load is

zaharov [31]

Answer:

$\frac{d_f}{d} =0.9999983$

Explanation:

Given:

force applied on the copper wire, $F=7000\ N$

cross sectional area of the wire, $a=0.01\ m^2$

Poisson's ratio, $\mu=0.3$

we have, Young's modulus, $E=128\times 10^3\ MPa$

Stress induced due to the applied force:

$\sigma=\frac{F}{a}$

$\sigma=\frac{7000}{0.01}$

$\sigma=700000\ Pa=0.7\ MPa$

Now the longitudinal strain:

$\epsilon=\frac{\sigma}{E}$

$\epsilon=\frac{0.7}{128\times 10^3}$

$\epsilon=5.468\times 10^{-6}$

Now from the relation of Poisson's ratio:

$\mu=\frac{\nu}{\epsilon}$

where:

$\nu=$ lateral strain

$0.3=\frac{\nu}{5.468\times 10^{-6}}$

$\nu=1.6406\times 10^{-6}$ ..................(1)

Now we find the diameter of the wire:

$a=\pi.\frac{d^2}{4}$

$0.01=\pi\times \frac{d^2}{4}$

$\frac{0.04}{\pi} =d^2$

$d=0.1128\ m=112.8\ mm$

When the tensile load is applied its diameter decreases:

The lateral strain is also given as,

$\nu=\frac{\Delta d}{d}$

$1.6406\times 10^{-6}=\frac{\Delta d}{112.8}$

$\Delta d=0.000185\ mm$

Now the final diameter will be:

$d_f=d-\Delta d$

$d_f=112.8-0.000185$

$d_f=112.799815\ mm$

Now the ratio:

$\frac{d_f}{d} =\frac{112.799815}{112.8}$

$\frac{d_f}{d} =0.9999983$

6 0

3 years ago

I will fan and give 2 medals!!!!!!!!!!!

IgorC [24]

Anything can happen once. You want to be able to show consistency and have more people confirm your answer

6 0

3 years ago

A police car sounding a siren with a frequency of 1280Hz is traveling at 120.0km/h. (a) What frequencies does an observer standi

Mariulka [41]

Answer:

a) 1417 Hz

b) 1314 Hz

Explanation:

The euqation for the Doppler effect frequency shift is:

$f = (\frac{c + vr}{c + vs})$

Where:

c: speed of sound (343 m/s in normal atmospheric conditions at sea level)

vr: speed of the receiver (negative if moving away from source, positive otherwise)

vs: speed of the source (positive if moving away from receiver, negative otherwise)

For the case of a standing observer:

120 km/h = 33.3 m/s

$f = (\frac{343 + 0}{343 - 33.3}) = 1417 Hz$

For the case of the car travelling at 90 km/h:

90 km/h = 25 m/s

$f = (\frac{343 - 25}{343 - 33.3}) = 1314 Hz$

5 0

4 years ago

An object is at x = 0 at t = 0 and moves along the x axis according to the velocity–time graph in Figure P2.50.(a) What is the o

bezimeni [28]

Picture? I may be able to answer if you have a chart or some kind of graph as a referral to the question

8 0

3 years ago

If a small-diameter open glass tube is partially immersed in a vessel containing mercury, the surface of the mercury inside the

Eduardwww [97]

The question comes along these answer choices:

A. lower than the mercury in the vessel, and shaped like the outside of an umbrella.

B. higher than the mercury in the vessel, and shaped like the outside of an umbrella.

C. lower than the mercury in the vessel, and shaped like the inside of a bowl.

D. higher than the mercury in the vessel, and shaped like the inside of a bowl.

Answer: option A. lower than the mercury in the vessel, and shaped like the outside of an umbrella.

Explanation:

That is what is called convex meniscus and is due to the high cohesion forces of mercury.

There are two opposing forces that take place in the formation of the meniscus: the cohesion, which is the attraction of the liquid mercury atoms among each other, and the adhesion, which is the attraction of mercury atoms to the molecules on the glass tube's walls (polar molecules of the glass tube).

Since, in mercury the cohesive forces (between the mercury atoms) are stronger than the adhesive forces (between mercury atoms and the glass tube's molecules), the cohesion overcomes the adhesion, meaining that the atoms try to remain together and, therefore, form the convex meniscus. Since the glass tube is upside down, the surface of the mercury inside of tube will be lower than the mercury in the vessel, and shaped like the outside of an umbrella.

3 0

4 years ago

Read 2 more answers