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IrinaK [193]
3 years ago
12

Which of the following statements is true? The melting and freezing points of a substance are the same. The melting and boiling

points of a substance are the same. The freezing and boiling points of a substance are the same. The heat of fusion and the heat of vaporization for a substance are the same.
Physics
2 answers:
insens350 [35]3 years ago
4 0
<span>The melting and freezing points of a substance are the same.

Substances melt and freeze at the same temperature. Hope this helps! :)</span>
ZanzabumX [31]3 years ago
4 0

Answer:

The melting and freezing points of a substance are the same

Explanation:

Melting occurs when the state of a substance changes from solid to liquid, while freezing occurs when the state of a substance changes from liquid to solid. Therefore, melting and freezing are one the inverse process of the other: it means that they occur at the same temperature.

For instance, the melting point of ice (at standard pressure) is 0^{\circ}, and the freezing point of water is at the same temperature, 0^{\circ}.

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A mass spectrometer was used in the discovery of the electron. In the velocity selector, the electric and magnetic fields are se
Mama L [17]

Answer:

Explanation:

Radius of dee, r = 8 mm = 0.008 m

Electric field, e = 400 V/m

Magnetic field, B = 4.7 x 10^-4 T

mass of electron, m = 9.1 x 10^-31 kg

charge of electron, q = 1.6 x 10^-19 C

(a) Let v is the speed of electrons.

v = \frac{Bqr}{m}

v = \frac{4.7\times 10^{-4}\times 1.6\times 10^{-19}\times 0.008}{9.1 \times 10^{-31}}

v = 661098.9 = 661099 m/s

(b)

\frac{e}{m}=\frac{1.6 \times 10^{-19}}{9.1\times 10^{-31}}

e / m = 1.76 x 10^14 C / kg

(c) Let K be the kinetic energy

K = 0.5 x mv²

K = 0.5 x 9.1 x 10^-31 x 661099 x 661099

K = 1.99 x 10^-19 J

K = 1.24 eV

So, the potential difference is

V = 1.24 V

(d) if the acceleration voltage is doubled

V = 2 x 1.24 = 2.48 V

So, Kinetic energy

K = 2.48 eV

K = 2.48 x 1.6 x 10^-19 = 3.968 x 10^-19 J

Let v is the speed

K = 0.5 x mv²

3.968 x 10^-19 = 0.5 x 9.1 x 10^-31 x v²

v = 933856.5 m/s

Let the new radius is r.

r=\frac{mv}{Bq}

r=\frac{9.1\times 10^{-31}\times 933856.5}{4.7\times 10^{-4}\times 1.6\times 10^{-19}}

r = 0.0113 m = 1.13 cm

7 0
3 years ago
Pressure of gas is 13.6 cm of hg what does it means​
vlada-n [284]

Explanation:

13 cmHg (centimeters of mercury) is the pressure at the bottom of a column of mercury 13 cm deep.  It is the equivalent of about 17.3 kPa or 2.5 psi.

5 0
3 years ago
A 70.0 kg astronaut is training for accelerations that he will experience upon reentry. He is placed in a centrifuge (r = 15.0 m
Levart [38]

Answer:

1.3823 rad/s

20.7345 m/s

28.66129935 m/s²

a=2.92164g

2006.29095 N radially outward

Explanation:

r = Radius = 15 m

m = Mass of person = 70 kg

g = Acceleration due to gravity = 9.81 m/s²

Angular velocity is given by

\omega=13.2\times \dfrac{2\pi}{60}\\\Rightarrow \omega=1.3823\ rad/s

Angular velocity is 1.3823 rad/s

Linear velocity is given by

v=r\omega\\\Rightarrow v=15\times 1.3823\\\Rightarrow v=20.7345\ m/s

The linear velocity is 20.7345 m/s

Centripetal acceleration is given by

a_c=r\omega^2\\\Rightarrow a_c=15\times 1.3823^2\\\Rightarrow a_c=28.66129935\ m/s^2

The centripetal acceleration is 28.66129935 m/s²

Acceleration in terms of g

\dfrac{a}{g}=\dfrac{28.66129935}{9.81}\\\Rightarrow a=2.92164g

a=2.92164g

Centripetal force is given by

F_c=ma_c\\\Rightarrow F_c=70\times 28.66129935\\\Rightarrow F_c=2006.29095\ N

The centripetal force is 2006.29095 N radially outward

The torque will be experienced when the centrifuge is speeding up of slowing down i.e., when it is accelerating and decelerating.

3 0
3 years ago
A ________ is a government-regulated maximum price for goods.
Simora [160]
<span>D. price ceiling
</span><span>This is a government regulation that establishes a maximum price for a particular good.</span><span>

</span>
8 0
3 years ago
An analogy makes a comparison between objects based on their similar qualities. Cassidy wanted to create an analogy for the moti
user100 [1]
The three phases of matter differ in properties just because of the proximity of their molecules. The solid phase is the most organized of all. Its atoms are compactly arranged together and has the strongest intermolecular forces to keep them together. This is why they have a definite shape and volume. The liquid phase have molecules that are far away from each other, but not as far as that of the gas phase. The liquid and gas phases can be lumped into one group called fluids because they have the same property - they take the shape and volume of their container.

To make an analogy, see the attached picture for your reference.

8 0
3 years ago
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