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3 years ago

Explain why dogs pant during hot summer days using the concept of evaporation?

1 answer:

6 0

Because dogs have their bodies covered with fur, sweating is less effective. Dogs have sweat glads in places where there is little fur. However this is not enough in some hot days. To keep the body temperature in order dogs have to rely on panting. The interior of mouth and lungs is wet, so breathing quickly speeds up cooling. It acts similarly to wind blowing on sweaty person's skin.

You can try it on your own. When you breathe heavily you will feel coolness :)

In order to evaporate (change state from liquid to gas) heat energy has to be delivered to water. The heat energy is taken from the body of dog, thus cooling it.

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Based on this electric field diagram, which statement best compares the charge of A with B?

lilavasa [31]

Based on this electric field diagram, the statement which best compares the charge of A with B is "A is negatively charged and B is positively charged. The charge on A is greater than that on B".

Answer: Option A

Explanation:

The charge is quantized represented as elementary charge, about 1.602×10−19 coulombs. Their are two kinds of electric charging: positive and negative (usually transported, separately, by protons and electrons). Like charges repel each other, while attraction occurs among unlike charges. An entity without net charge is considered neutral. If a piece of matter comprises more electrons than protons, it has a negative charge, when there are fewer, it'll have a positive charge and when there are equal amounts, this will be neutral.

4 0

3 years ago

A stretched string has a mass per unit length of 5.40 g/cm and a tension of 17.5 N. A sinusoidal wave on this string has an ampl

kondaur [170]

Answer:

Part a)

$y_m = 0.157 mm$

part b)

$k = 101.8 rad/m$

Part c)

$\omega = 579.3 rad/s$

Part d)

here since wave is moving in negative direction so the sign of $\omega$ must be positive

Explanation:

As we know that the speed of wave in string is given by

$v = \sqrt{\frac{T}{m/L}}$

so we have

$T = 17.5 N$

$m/L = 5.4 g/cm = 0.54 kg/m$

now we have

$v = \sqrt{\frac{17.5}{0.54}}$

$v = 5.69 m/s$

now we have

Part a)

$y_m$ = amplitude of wave

$y_m = 0.157 mm$

part b)

$k = \frac{\omega}{v}$

here we know that

$\omega = 2\pi f$

$\omega = 2\pi(92.2) = 579.3 rad/s$

so we have

$k = \frac{579.3}{5.69}$

$k = 101.8 rad/m$

Part c)

$\omega = 579.3 rad/s$

Part d)

here since wave is moving in negative direction so the sign of $\omega$ must be positive

4 0

3 years ago

Density is given in ____. a. Pa/cm3 c. g/s2 b. N/m2 d. g/cm3

Ainat [17]

Density is defined as [mass] / [volume] .

The only choice listed with those physical dimensions is 'd' .

3 0

3 years ago

How do you calculate the mass of an object accelerating at22.35m/s2 with a force of 120N

Arte-miy333 [17]

Answer:

The mass of object is calculated as 5.36 kg

Explanation:

The known terms to find the mass are:

acceleration of object (a) = 22.35 $m/s^{2}$

Force exerted (F) = 120N

mass of an object (m) = ?

From Newton's second law of motion;

F = ma

or, 120 = m × 22.35

or, m= $\frac{120}{22.35}$ kg

∴ m = 5.36 kg

3 0

2 years ago

Energy is conserved. This means that in any system, _________. a) energy is constantly recycled b) total energy input equals tot

tangare [24]

Answer:

b) total energy input equals total energy output

Explanation:

The first law of thermodynamics is a generalization of the conservation of energy in thermal processes. It is based on Joule's conclusion that heat and energy are equivalent. But to get there you have to get around some traps along the way.

From Joule's conclusion we might be tempted to call heat "internal" energy associated with temperature. We could then add heat to the potential and kinetic energies of a system, and call this sum the total energy, which is what it would conserve. In fact, this solution works well for a wide variety of phenomena, including Joule's experiments. Problems arise with the idea of heat "content" of a system. For example, when a solid is heated to its melting point, an additional "heat input" causes the melting but without increasing the temperature. With this simple experiment we see that simply considering the thermal energy measured only by a temperature increase as part of the total energy of a system will not give a complete general law.

Instead of "heat," we can use the concept of internal energy, that is, an energy in the system that can take forms not directly related to temperature. We can then use the word "heat" to refer only to a transfer of energy between a system and its environment. Similarly, the term work will not be used to describe something contained in the system, but describes a transfer of energy from one system to another. Heat and work are, therefore, two ways in which energy is transferred, not energies.

In an isolated system, that is, a system that does not exchange matter or energy with its surroundings, the total energy must remain constant. If the system exchanges energy with its environment but not matter (what is called a closed system), it can do so only in two ways: a transfer of energy either in the form of work done on or by the system, either in the form of heat to or from the system. In the event that there is energy transfer, the change in the energy of the system must be equal to the net energy gained or lost by the environment.

6 0

3 years ago