what is physics and important of physics​

Answer:

Gravitational fields are determined only by the mass ( or mass-energy) of a body. ... magnetic fields are produced by charged particles in motion, and depend on the charge and velocity of these particles, but not on their mass. Magnetic fields are 'polar' fields with a North and South polarity.

Explanation:

Answer:

The pressure at the bottom of the river is less than that at the bottom of the lake.

Explanation:

From Bernoulli's equation, the pressure difference is given by

ΔP = ρgΔh + ρ(v₂² - v₁²)/2 where ρ = density of water, g = acceleration due to gravity, Δh = depth, v₁ = velocity at top, v₂ = velocity at bottom

For the lake, v₁ = v₂, since the velocity at the top and bottom are the same. So,

ΔP₁ = ρgΔh + ρ(v₁² - v₁²)/2 = ρgΔh + 0 = ρgΔh

P₂ - P₁ = ρgΔh

P₂ = P₁ + ρgΔh

For the river, v₁ < v₂, since the velocity at the top of the river is greater than at the bottom.

So,

ΔP₂ = ρgΔh + ρ(v₂² - v₁²)/2.

Since  v₁ < v₂, ρ(v₂² - v₁²)/2 will be negative,

So,

ΔP₂ = ρgΔh - ρ(v₂² - v₁²)/2.

Since ρ(v₂² - v₁²)/2 is negative, making ΔP less than that in the lake.

So, ΔP₂ = ΔP₁ -  ρ(v₂² - v₁²)/2.

ΔP₂ = P₃ - P₁

P₃ - P₁ = P₂ - P₁ -  ρ(v₂² - v₁²)/2.

P₃ = P₂ - ρ(v₂² - v₁²)/2.

where P₃ = pressure at bottom of the river and P₂ = pressure at bottom of the lake and P₁ = atmospheric pressure at top of river and lake respectively.

Since the factor ρ(v₂² - v₁²)/2 is removed from the pressure at the bottom of the lake, the pressure at the bottom of the river is therefore less than that at the bottom of the lake.

Answer:

Lens of the human Eye is a important and one of that most complex sense organ.

Explanation:

Lens of the human eye it helps that in visualizing light and color perception and objects , glance on the human eye structure and function.

Sense organs are much pretty similar to the camera they  help us see the objects clear.

A human eye is the 2.3 cm in diameter and all filled some fluid, and there are following parts in eye:-  cornea,  Retina , Lens ,Pupil , optic nerves.

cornea :- the cornea is the first transparent part of is called cornea, enters the light through the cornea.

Retina :-it is light sensitive layer that consists of nerve cells,then transmitted to the brain through nerves.

Lens:- behind the pupil there is a transparent structure called lens,it shape focus light on the retina.

Pupil:-it control the value of light that enters the human eye.

Optic nerves is are the two types :- (1) cones (2) Rods .

Answer:

It causes Light Rays to converge on the retina

Explanation:

I took the K12 Test

Answer:

A: 15 m/s

B: 900 Meters

Explanation:

A. Average speed is equal to final velocity plus initial velocity divided by two

Va= (20+10)/2 = 15 m/s

B.

distance = speed × time

D= 15 m/s * 60s = 900 Meters

Answer:

Answer is in the attachment.

Explanation:

Hope this helps.

Please mark me as Brainliest.

Answer:

It will fall at the same speed in both locations

Explanation:

When an object is falling, it is accelerated to the same degree irrespective of the height from which it is falling.

All objects on the earth's surface experience an acceleration due to gravity. This acceleration due to gravity is the same for all objects irrespective of their height or mass.

Hence for a stone dropped from the same height as Terai and the top of a mountain, the acceleration due to gravity is the same in both cases hence they will fall at the same speed.

Answer:

The answer is below

Explanation:

The efficiency of a machine is the ratio of its output to its input. The efficiency shows how effective the machine by the way it converts the input energy into work. The higher the efficiency of the machine the more effective it is. The efficiency is usually less than 1.

Given that the machine uses diesel oil (input) that can produce 3.0 x 10⁹ J of energy while the work performed by the machine (output) is 2.7 x 10⁸ J. The efficiency is given as:

Efficiency = output / input = 2.7 x 10⁸ J / 3.0 x 10⁹ J = 0.09 = 9%

This means that the machine is not effective because of its low efficiency

Answer:

$876.96

Explanation:

The energy used is:

3500 W × (24 hr/day) × (120 day) × (1 kW / 1000 W) = 10,080 kWh.

So the cost is:

10,080 kWh × ($0.087 / kWh) = $876.96

Answer:

a)  T = 1.26 s , b)  v_max = 0.14 m / s ,  a_max = 0.7 m / s²

c) x = 0.028 cos (5 t) ,    v = - 0.14 sin 5t,   a = - 0.7 cos 5t

Explanation:

This is a simple harmonic motion exercise that is described by the equation

    x = A cos (wt +Ф)

with

          w = √ (k / m)

let's apply this expression to our case

a) Angular velocity is related to frequency

          w = 2π f

frequency and period are related

          f = 1 / T

we substitute

         2π / T = √ (k / m)

         T = 2π √(m / k)

let's calculate

         T = 2π √(1/25)

          T = 1.26 s

In the expression for the period, the amplitude does not appear, therefore there is no dependence, as long as Hooke's law is fulfilled, which is correct for small amplitudes.

b) in the initial equation we have the position as a function of time, let's use the definition of speed and acceleration

           v = dx / dt

           v = - A w sin (wt + Ф)

the speed is maximum when the sine is -1

            v_max = A w

            w = √ (k / m)

            w = √ 25/1

            w = 5 rad / s

the amplitude of the movement is equal to the maximum compression of the spring

            A = 2.8 cm = 0.028 m

we substitute

            v_max = 0.028 5

            v_max = 0.14 m / s

acceleration

             a = dv / dt

             a = - A w² cos (wt + Ф)

the acceleration is maximum when the cosine is -1

             a_max = A w²

let's calculate

             a_max = 0.028 5²

             a_max = 0.7 m / s²

c) let's start by finding the phase constant

              v = -A w cos (wt + Ф)

at t = 0 they indicate that the system has v = 0

              0 = -A w sin (0 + Ф)

              Ф = sin⁻¹ 0

              Ф = 0

we write the equation

            x = 0.028 cos (5 t)

           v = - A w sin (wt + Ф)

           v = - 0.028 5 sin (5t + 0)

           v = - 0.14 sin 5t

acceleration

           a = - A w² cos (wt + Ф)

           a = - 0.028 5 2 cos (5 t + 0)

           a = - 0.7 cos 5t

Answer: √(L/g)

Explanation:

Here we only work with the units:

The unit of the period is units of time, so we have:

[T] = [s]

Now, the units of the length of the pendulum are units of distance:

[L] = [m]

And the units of the acceleration are:

[g] = [m/s^2]

Now, we want to work with those two in such way that the end result is only in seconds.

First, we can see that in g we have seconds square, so we know that we should use a square root.

Then we can divide L by g in order to remove the distance unit, and to have the time unit in the numerator

[L/g] = [m*s^2/m] = [s^2]

Now we apply the square root:

[√(L/g)] = [√s^2] = [s]

Then the combination is: √(L/g)

T = k*√(L/g)

where k is the constant of proportionality.

Answer: 37.5 km

Explanation:

The question is that

If you ran 15 km/hr for 2.5 hours, how much distance would you cover ?

Where

Speed = 15 km/ hr

Time = 2.5 hours

Using the formula for speed.

Speed = distance/time

Substitute speed and time into the formula

15 = distance/ 2.5

Make distance the subject of formula by cross multiplying.

Distance = 15 × 2.5

Distance = 37.5 km.

Answer:

Reproducible by other scientists

Explanation:

I just took the test

Answer:

When we have irregular objects, it may become very hard to calculate the volume of the object, as we actually can not use any simple equation to find it.

The mass is less tricky, just find a scale and wheight it, now we know the mass of the irregular object.

One way to measure the volume of the object is using water... how we do it?

Get some recipient with water, measure the height of the water.

Introduce your object into the water and totally submerge it, now the level of the water will rise. This is because as you introduce the object under the water, you are displacing up a given volume of water that has the same volume as the irregular object.

Now that you know the height of the water before and after you put your object, you can easily calculate the volume of water displaced, and that will be the volume of the object (the tricky part may be totally submerging the object if, for example, is wood and it floats, here you can use a thin wire to push it down but it will affect a little bit the measures.)

Answer:

football

Explanation:

I took the 2.10 quiz and got it wrong so it must be football

Answer:

My answer is radiant energy to chemical energy because it uses the sun which is a form of solar energy and then converts the food to chemical energy for the plant itself

Answer: Radiant energy to chemical energy

Explanation: Right on edge2021

Answer:

12.3 m/s

Explanation:

The Doppler equation describes how sound frequency depends on relative velocities:

fr = fs (c + vr)/(c + vs),

where fr is the frequency heard by the receiver,

fs is the frequency emitted at the source,

c is the speed of sound,

vr is the velocity of the receiver,

and vs is the velocity of the source.

Note: vr is positive if the receiver is moving towards the source, negative if away.

Conversely, vs is positive if the receiver is moving away from the source, and negative if towards.

Given:

fs = 894 Hz

fr = 926 Hz

c = 343 m/s

vs = 0 m/s

Find: vr

926 = 894 (343 + vr) / (343 + 0)

vr = 12.3

The speed of the car is 12.3 m/s.

Explanation:

Hi,

The answer is friction.

There is almost no machine which are not affected by friction. It losts some work due to friction while working.

Hope it helps..

Answer:

friction

Explanation:

the other options dont effect efficiency

Answer:

Explanation:

On rubbing a glass rod with silk, the electrons from the glass rod get transferred to the silk. The silk now has an excess of electrons and so is negatively-charged. On the other hand, the glass rod is deficient in electrons and hence is positively-charged.

In the above case, the silk undergoes negative electrification.

Now, when the positively charged glass rod is touched on the disc of a negatively charged gold leaf electroscope, the electrons shifts towards rod, hence amount of charge on gold leaves decreases and the divergence between the gold leaves decreases as unlike charges attract each other.

Hence, the divergence decreases when a glass rod rubbed with silk is brought near the disc of negatively charged electroscope.

hope it helps pls mark me as brainliest

Answer:

White light contains seven colors, which are separated by the prism.

White light reacts with chemicals in the air to produce seven colors.

Explanation:

It was first observed by Sir Issac Newton, that when white light is passed through a prism, an elongated, coloured patch of light is obtained on a screen placed behind the prism. The seven colours obtained constitute the spectrum of white light.

In nature, white light is separated into its constituent wavelengths when white light interacts with substances in the atmosphere.

Answer:

The correct answer is “color is an impurity added to white light by the prism.”

and

“White light contains seven colors, which are separated by the prism

Explanation:

Answer:

Explanation:

The weight of a body is defined as the force with which it is attracted towards the centre of a planet. A spring balance measures it. It's unit is Newton ( N ) in the SI system and dyne in the CGS system.

Hope I helped!

Best regards!

Weight is force.

The CGS unit of force is the dyne.

The SI unit of force is the Newton.

Answer:

Solution

Given:

initial velocity (u)=0m/s (because an object

starts from the rest)

time (t)=3sec

diatance travelled(s)=14m(16-2=14)

acceleration (a)=?

Now,

According to the formula

s=ut+1/2at^2

or,14 =0×3+1/2×a×3^2

or, 14=0+a/2×9

or, 14=9a/2

or, 9a=28

or, a=28/9

or, a=3.1 m/s^2

Therefore, the acceleration of the object is 3.1m/s^2 ans.

Ignoring the air resistance it will take about 3 seconds for the object to reach the ground.We know that the acceleration due to gravity is 10m/s2.

We also know that the final velocity is 30 m/s while the initial velocity is 0 m/s

we can use the formulae for acceleration to calculate the time taken/

(final - initial velocity)/timetaken=10

(30-0)/timetaken=10

timetaken =30/10=3 seconds

Explanation:

The ratio of the areas is the square of the ratio of the radii.

A/A = 3.16² = 9.99

The ratio of the volumes is the cube of the ratio of the radii.

V/V = 3.16³ = 31.6

Answer:

C. Meter

Explanation:

The International System of Unit (SI) is gotten from the french word Systeme international is a modern form of metric measurement. It is the system of measurement that is universally accepted. It is from this SI units that all other system of units are derived. There are seven basic SI units which are:

1) Length in Meter (m)

2) Time in Seconds (s)

3) Amount of Substance in mole (m)

4) Electric current in ampere (A)

5) Temperature in kelvin (k)

6) Luminous intensity in candela (cd)

7) Mass in kilogram (kg)

Answer:

Explanation:

In all works of life science can be applied, in-fact science has already been applied already, even in the humanities, social sciences and art related studies sciences is being applied,

    Furthermore, the application of science and technology knows no boundaries, and as science is advancing day by day, expanding to new frontiers and breaking new limits so is it application to all works of life and relevance everyday.

Answer:

In what way is iron unique among the elements?

It has the lowest mass per nuclear particle.

Match words at the left to the correct blanks in the sentences on the right. Not all words will be used.

-The energy that drives the expansion of a star into a subgiant or red giant comes from HYDROGEN SHELL FUSION

-Stars with mass greater than about 8 solar masses are considered HIGH-MASS STARS

-The final stage of core fusion in a low-mass star is HELIUM FUSION

-Stars that are fusing hydrogen in their cores are MAIN-SEQUENCE STARS

-When it dies, a high-mass star explodes as a SUPERNOVA

-A star that is expanding (into a subgiant and then a giant) has a(n) INERT HELIUM CORE

-When it dies, a low-mass star expels a PLANETARY NEBULA

-Stars with masses less than about two solar masses are considered LOW-MASS STARS

Answer:

D

Explanation:

The answer is D because:

A) Only doctors are allowed to prescribe medications.

B) Rita is not a chef/cook.

C) Rita is not a personal trainer

D) The job of a dietican is to provide reccomendations to their clients in order for them to implement a healthy lifestyle via consuming what is best for them.

Hope this helps :)

Answer:

D.) Making recommendations for healthy eating habits

Explanation: PLATO :)))

Answer:

10.44° per sec

Explanation:

Initial angular speed N = 2 rotations per minute

converting to rad/s ω = 2πN/60 = (2 x 3.142 x 2)/60 = 0.21 rad/s

the initial radius of the disk = 16 cm = 0.16 m

final radius = 17 cm = 0.17 m

Angular momentum = [tex]I[/tex]ω

where [tex]I[/tex] = rotational inertia = mass x [tex]radius^{2}[/tex]

ω = angular speed

For the initial case

[tex]I[/tex] = m x [tex]0.16^{2}[/tex] = 0.0256m

Angular momentum = 0.0256m x 0.21 = 0.0054m

For second case

[tex]I[/tex] = m x [tex]0.17^{2}[/tex] = 0.0289m

Angular momentum = 0.0289m x ω = 0.0289mω

For conservation of rotational momentum, initial angular momentum must be equal to the final angular momentum

0.0054m = 0.0289mω

m cancels out, we have

0.0054 = 0.0289ω

ω = 0.187 rad/s

converting back to rpm, we have

N = 0.187/2π = 0.029 rotations per sec

0.029 x 360 = 10.44° per sec

Answer:

  #_total = 4.38 10⁹ liter

Explanation:

For this exercise we can use a direct proportion rule (rule of three). If 4 people use 1200 liters how much water 1 person consumes

            #_water = 1 person (1200 liter / 4 person)

            #water = 300 liters

Now we look for the consumption of this person in a year, if 1 person consumes 300 liters 1 day, how many liters they consume in a year (365 days)

           #_water_person_total = 365 days (300 liters / 1 day)

           #_water_person_total = 109500 liters

This is the water consumption of 1 person in a year, the total of 40000 people how much they consume

           #_total = 40000 person (109500 liter / 1 person)

           #_total = 4.38 10⁹ liter

Answer:

Pressure

Explanation:

One of the theories propounded by the Kinetic molecular theory, and which also provides an explanation of the several gas laws, is the statement that the gas molecules in a container, travel in straight lines and are in constant collision with themselves and the walls of the container, thus exerting force. This force is the pressure which is defined as the force per unit area.

There is no loss of energy in the collisions involving the gas molecules and that is why their movement can be described as elastic. The descriptions of the behavior of gas molecules in the Kinetic Molecular Theory, give rise to Charles law, Boyle's Law, Avogadro's Laws, Dalton's Law, and Amonton's Law.

Answer:

The pressure

Explanation:

Molecules of gases are constantly in motion, colliding with the walls of their container. This constant collision impacts force on the walls of the container, which depends on the speed with which the molecules are moving. The speed with which these molecules travel depends on the average kinetic energy of the molecules, which is proportional to the temperature.

This force when exerted per unit area is the pressure the gases exert on the walls of the container.