physics as a subject involves measurement and estimation,giving examples of everyday life situations, explain the meaning and what is done in each case​

When,a man stands still on a moving walkway that is going at a speed of 0.2 m/s to the west,then the velocity of the man according to a stationary observer would be 0.2 m/s west,Therefore, the correct answer would be option B.

The total displacement covered by any object per unit of time is known as velocity. The velocity of an object is depend on the magnitude as well as the direction of the object.

the mathematical expression for velocity is given by

velocity = total displacement /time

The speed and velocity of the object are very different from each other because speed does not depend upon the direction of the moving  object but velocity depends on the magnitude of speed as well as the direction of the moving object.

As per given in the problem a man stands still on a moving walkway that is going at a speed of 0.2 m/s to the west therefore from the perspective  of a stationary observer the velocity of man would be 0.2 m/s towards West.

Hence the correct options for the problem would be option B.

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Answer:

La materia es la sustancia de la que está hecho todo material. En física, el sistema es una de las propiedades de la materia. Se puede transferir entre objetos y convertir en forma. No se puede crear ni destruir.

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Answer:

the magnetic compass is used to determine direction because it is one of the most accurate form of magnet as we already know that a freely suspended magnet always faces towards north direction and south direction

Answer:

42g

Explanation:

the mass of a body is given by

m=weight/gravity

=420/10

=42

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Answer:

if buoyant force is equal is equal to the weight of body then our body float. if density of our body is less than density of liqiud then our body float in water.

Answer:

D

Explanation:

i just did it trust me

Answer:

A

Explanation:

i think a is the answer because if you take an example of group 1 and 2 metals on the periodic table you will notice that they are highly reactive but they have a few electrons in their outer most shells.

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Answer:

option a negative to positive

Explanation:

The flow of electrons is termed electron current. Electrons flow from the negative terminal to the positive. Conventional current or simply current, behaves as if positive charge carriers cause current flow. Conventional current flows from the positive terminal to the negative

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Answer:

ccccccccc or bbbbbbb or aaaaaaaa or ddddddd

Answer:

A. When the independent variable is continuous and shows a causal link to the dependent variable.

Explanation:

A graph can be defined as the graphical representation of data (informations) on horizontal and vertical lines i.e x-axis and y-axis respectively.

In an experiment , the variable being manipulated by an experimenter is known as an independent variable while the dependent variable is the event expected to change when the independent variable is manipulated

Generally, a line graph should be used when the independent variable is continuous and shows a causal link to the dependent variable.

This ultimately implies that, a line graph should be used when the data changes continuously over time and as such there exist a linear relationship between the data (variables).

Momentum is a quantity that we can say is typically conserved in collisions.

Momentum is the quantity that that we see typically conserve in the collision,therefore the correct answer is the option A

It is the type of collision in which the total momentum  as well as the kinetic energy on the system is conserved .The momentum before the collision is equal to the momentum after the collision in other words one can say in the elastic collision momentum of the quantity is conserved.

In the inelastic collision the momentum is conserved but the kinetic energy of the quantity is not conserved.

Momentum of a quantity is conserved irrespective of the type of collision  whether it will be elastic collision or inelastic collision the momentum of the quantity will always be conserved.

Hence,we can say that momentum is the quantity that is conserved in collision,The correct answer for the given problem is option A.

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Answer:

The person feels cool at first because the swimming pool water is usually cool and he/she has that water on his body. But when it evaporates, the cool air directly touches his body and that's why he/she feels cold.

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Answer:

Yes, this is true.

-- While the apple is falling, the same gravitational force acts on both the apple and the Earth.

-- The mass of the apple is somewhere in the neighborhood of 1/4 kg.

-- The mass of the Earth is about 5.972 x 10²⁴ kg.

-- Since the Earth has roughly 2.389 x 10²⁶ times as much mass as the apple has, the apple has roughly 2.389 x 10²⁶ greater acceleration than the Earth has, and moves roughly 2.389 x 10²⁶ times as far down as the Earth moves up, before they smack together.

-- That's why you don't notice the Earth's motion.

-- Also, you're standing on the Earth, moving up with it, toward the apple.  Maybe it would be different if you were sitting on the apple, riding it down to the ground, and you were able to notice the motion of the ground coming up to meet you at a speed that's 0.00000000000000000000000000419 of YOUR speed.  

Answer From Gauth Math

Answer:

250 Pa or N/m^2

Explanation:

Pressure(P)=F/A=500/2=250 Pa or N/m^2

Answer:

is 10³

Explanation:

cuz the formula of KE is 1/2mv²

covert 50g to kg first then plug in the formula

1/2 × 0.05 × 200 = 10³ J

Answer:

3:00 - 3:02 and 3:07 - 3:08

Explanation:

Those are the only intervals in which Jenny's speed increased.

Answer and Explanation:

To know where Jenny was positively accelerating, we have to find where the slopes on the graph are increasing (in the positive direction).

By looking at the graph, we can see that at the intervals:

3:00 to 3:02 and 3:07 to 3:08

Jenny was positively accelerating, as there is an increase in speed during these time intervals.

#teamtrees #PAW (Plant And Water)

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Answer:

Acceleration, rate at which velocity changes with time, in terms of both speed and direction. A point or an object moving in a straight line is accelerated if it speeds up or slows down. ... Acceleration is defined as the change in the velocity vector in a time interval, divided by the time interval.

Answer:

The rate of change in velocity with time A=finall velocity _intial velocity upon time

Part A - The apparent displacement of the mark is 4 cm.

The refractive index of a material, n = real depth, D/apparent depth, L.

So, n = D/L

Since the refractive index of the triangular glass prism is 1.5, n = 1.5. Also, the triangular glass prism is 12 cm thick and placed on a mark on a piece of paper resting on a horizontal bench. So, the real depth of the mark on the piece of paper through the triangular prism is D = 12 cm and its apparent depth is L.

Since n = D/L,

making L, subject of the formula, we have

L = D/n

Substituting the values of the variables into the equation, we have

L = D/n

L = 12 cm/1.5

L = 8 cm

so, the apparent depth of the mark is 8 cm.

So, the apparent displacement of the mark is d = D - L = 12 cm - 8 cm = 4 cm

Thus the apparent displacement of the mark is 4 cm.

Part B - The refractive index of water, n = 1.33.

The refractive index of a material, n = real depth, D/apparent depth, L.

So, n = D/L

Since the depth of water in the jar is 24 cm, the real depth, D = 24 cm.

Also, the bottom of the jar appears to be raised by 6 cm. So, the apparent depth, L = 24 cm - 6 cm = 18 cm

Since n = D/L, the refractive index of water n = D/L

Substituting the values of the variables into the equation, we have

n = D/L

= 24 cm/18 cm

= 1.33

So, the refractive index of water, n = 1.33.

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Answer:

Explanation:

We are basically needing to solve for the time in the equation d = rt, where d is the distance around Mars (aka the circumference), r is the velocity, and t is time. We need to find the circumference and the velocity. We will begin with the velocity.

Because the gravitational attraction between Phobos and Mars provides the centripetal acceleration necessary to keep Phobos in its (sort of) circular path, the equation we use for this is:

[tex]F_g=F_c[/tex] which says that Force supplied by gravity is equal to the centripetal force. Expanding that:

[tex]\frac{Gm_{Phobos}m_{Mars}}{r^2}=\frac{m_{Phobos}v^2}{r}[/tex]

When we move that around mathematically to solve for the velocity value, what we end up with is:

[tex]v=\sqrt{\frac{Gm_{Mars}}{r}[/tex] and filling in:

[tex]v=\sqrt{\frac{(6.67*10^{-11})(6.42*10^{23})}{9.38*10^6} }[/tex] and we get that

v = 2100 m/s

Now for the circumference:

C = 2πr and

C = 2(3.1415)(9.38 × 10⁶) so

C = 5.9 × 10⁷

Putting that all together in the C = vT equation:

5.9 × 10⁷ = 2100T so

T = 2.8 × 10⁴ sec or 7.8 hours

Answer:

Explanation:

The heat from the Sun gets to the surface of the Earth by radiation and not by convection because:

i. Radiation does not require material medium for its propagation: Since the space between the Sun and Earth is a vacuum ( i.e it is an empty space), then the only method for the heat from to Sun to get to the Earth is by radiation. This method does not require a material medium, while convection is a method that requires material medium for its propagation.

ii. Radiation occurs without heating the intervening medium: During the propagation of the heat from the Sun to the Earth, the space between the two heavenly bodies is not heated up. Some fraction of the heat after hitting the surface of the Earth get reflected back into the Earth's atmosphere. While in convection, the medium would have been heated up in the process.

Answer:

  96 m

Explanation:

The average velocity over those 4 seconds is the velocity after 2 seconds:

  30 m/s -(2 s)(3.0 m/s^2) = 24 m/s

The displacement is the product of this average velocity and the duration of the acceleration:

  d = (24 m/s)(4 s) = 96 m

The boat covered 96 m while being accelerated.

Explanation:

Volume is the quantity of three-dimensional space enclosed by a closed surface

The si unit of mass is kilogram (kg) and the si unit of length is metre(m)

Explanation:

Density is mass in grams over volume in cubic centimeters.

So it is

[tex]\frac{4g}{5cm^{-3} }[/tex]  =  0.8 g/cm[tex]^{3}[/tex]  

The unit is grams per cubic centimeter.

NB - density can also be kilograms over cubic meters

Answer:

Current- the flow of free charges, such as electrons and ions

Drift velocity- the average speed at which these charges move

Answer:

An electric current is the stream of changed particals, such as electrons & ions, moving through an electrical conductor.

The average velocity attained bycharged partical ,such as electrons,in a material due to electric fields

Answer:

d

Explanation:

I'm not perfectly sure so check again

[tex]\\ \sf\longmapsto 300-70.5=229.5kJ[/tex]

We know

[tex]\boxed{\sf Efficiency=\dfrac{Used\:Energy}{Supplied\:Energy}\times 100}[/tex]

[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{300}\times 100[/tex]

[tex]\\ \sf\longmapsto Efficiency=\dfrac{229.5}{3}[/tex]

[tex]\\ \sf\longmapsto Efficiency=76.5\%[/tex]

Answer:

Those reaction in which one element replaces another element form its place is called Single displacement reaction