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3 years ago

Which of the following processes are Exothermic? I. Melting II. Sublimation III. Vaporization IV. Condensation

Physics

1 answer:

mariarad [96]3 years ago

7 0

Answer: condensation process is exothermic. The correct option is IV.

Explanation: Exothermic reaction is a chemical reaction in which heat is released to the surrounding environment.

condensation is defined as a process by which a medium changes from gaseous phase into liquid phase. Using water molecules to illustrate, to transform water molecules to gaseous phase it requires the heat of vaporization to be overcomed. This same hear of vaporization needs to be given off when changing back to liquid phase.

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Near the top of the Citigroup Center building in New York City, there is an object with mass of 4.00 ✕ 105 kg on springs that ha

jasenka [17]

Explanation:

It is given that,

Mass of an object, $m=4\times 10^5\ kg$

(a) Time period of oscillation, T = 2.4 s

The formula for the time period of spring is given by :

$T=2\pi \sqrt{\dfrac{m}{k}}$

Where

k is the force constant

$k=\dfrac{4\pi ^2 m}{T^2}$

$k=\dfrac{4\pi ^2 \times 4\times 10^5}{(2.4)^2}$

$k=2.74\times 10^6\ N/m$

(b) Displacement in the spring, x = 2.2 m

Energy stored in the spring is given by :

$U=\dfrac{1}{2}kx^2$

$U=\dfrac{1}{2}\times 2.74\times 10^6\ N/m\times (2.2\ m)^2$

$U=6.63\times 10^6\ J$

Hence, this is the required solution.

7 0

3 years ago

Two balls of unequal mass are hung from two springs that are not identical. The springs stretch the same distance as the two sys

IRISSAK [1]

Answer:

b) Springs oscillate with the same frequency,

Explanation:

expression for frequency of vibration of mass hanging from a spring is given as follows

f = $\frac{1}{2\pi} \times \sqrt{\frac{k}{m} }$

k is force constant of spring and m is mass vibrating .

In the present case, if mass stretches the spring by x and remains balanced

mg = k x

$\frac{k}{m} =\frac{g}{x}$

g and x are same for both cases

$\frac{k}{m}$ will also be same for both cases .

Hence frequency of vibration will also be same for both the balls .

4 0

3 years ago

A bolt is to be tightened with a torque of 7.0 N · m. If you have a wrench that is 0.55 m long, what is the least amount of forc

kodGreya [7K]

To solve this problem we will apply the given concept for torque which explains the relationship between the force applied and the distance to a given point. Mathematically this relationship is given as

$\tau = F*d \rightarrow F = \frac{\tau}{d}$

Where,

$\tau =$ Torque

F = Force

d = Distance

Our values are given as,

$\tau = 7.0Nm , d = 0.55m$

Therefore replacing we have that the force is

$F = \frac{7}{0.55}$

F = 12.72N

Therefore the least amount of force that you must exert is 12.72N

4 0

3 years ago

Hello please help i’ll give brainliest

Alja [10]

Answer:

First answer.

Explanation:

There may be a 5N force, but if the frictional force also equals 5N, than they cancel eachother out, resulting in the brick still staying still, as it is resting on a (perfectly) level surface, but any amount of force would make the brick move.

4 0

3 years ago

Which of the following equations represents the law of universal gravitation

Xelga [282]

<span>Newton's law of universal gravitation is an INVERSE SQUARE LAW, which rules out C and D.It is proportional to the masses involved, which rules out B.A could be seen as one form of the lawF=G m1 m1/r^2Though I recognise it more as F=G m1 m2/r^2.G is the universal gravity constant and is distinct from g which is the acceleration of gravity LOCAL to a planet or moon. So, g is LOCAL, G is universal.Newton was a smart bloke, as are all these scientists whose names frequently appear.
</span>

8 0

3 years ago