Which one of the following explains how light energy helps us see all kinds of objects around us?

a flashlight shining light on a book

Light is absorbed by the objects and does not reach our eyes.
The objects emit light that enters our eyes.
Light reflects off the objects and enters our eyes.
Light travels in a straight line until it enters our eyes.

Answer: option c

Because the height is increasing then decreasing

Answer:

given,

load = 400 N

effort = 100 N

load distance = 20 cm

we know that ,

E*Ed = L*Ld

=100 N* Ed = 400N * 20 cm

=100N * Ed = 8000N/cm

= Ed =( 8000N/cm ) / 100N

= Ed = 80 cm

b. soln.

given,

load = 600 N

load distance = 2 m

effort = 300 N

effort distance = ?

we know that ,

= E *Ed = L * Ld

= 300N * Ed = 600N * 2 m

= 300N * Ed = 1200N/m

=Ed =( 1200N/m ) / 300 N

= Ed = 4 m

C. soln.

given,

load = 600 N

load distance =20 cm

effort = 200 N

effort distance = ?

M.A = ?

V.R = ?

Efficiency = ?

we know that ,

= E *Ed = L *Ld

= 200N * Ed = 600 N * 20 cm

=200 N *Ed = 12000 N/cm

=Ed = ( 12000 N/cm) / 200 N

= Ed = 60 cm

Also,

M.A = load / effort

=600 N / 200 N

= 3

V.R = Ed/ Ld

= 60 cm / 20 cm

= 4

efficiency = ( M.A / V.R ) 100 %

= ( 3 / 4 ) 100%

= 75 %

d. soln.

given,

load = 600 N

load distance = 0.5 m

effort distance = 2.5 m

effort = ?

we know that ,

= E * Ed = L * Ld

= E * 2.5 m = 600 N * 0.5 m

= E * 2.5 m = 300 N / m

= E = ( 300 N / m ) / 2.5 m

= E = 120 N

its not in nurtal or park

Answer:

value of heat is 18 J

2. step by step

formular w=p(volume1-volume2)

w= 1.0×10^5(0.0006-0.0004)

w= 40 J

Answer:

Increase in μk

Explanation:

different ans set

We know

[tex]\boxed{\sf F_c=\dfrac{mv^2}{r}}[/tex]

[tex]\\ \sf\longmapsto F_c=\dfrac{20(10)^2}{4}[/tex]

[tex]\\ \sf\longmapsto F_c=\dfrac{20(100)}{4}[/tex]

[tex]\\ \sf\longmapsto F_c=\dfrac{2000}{4}[/tex]

[tex]\\ \sf\longmapsto F_c=500N[/tex]

The centripetal force on the truck can be determined from the mass, velocity and the radius of the circular path. The centripetal force acting on the truck is 500 N. Hence, option A is correct.

Centripetal force is a type force acting on an object traveling through a circular path. The centripetal force is the rotational analogue of the linear force.

The centripetal force acting on an object is related to the mass, velocity and radius of the circular path is given by:

Fc =  mv ²/r

Given that, mass of truck = 20 Kg

radius of circle = 4 m

velocity = 10 m/s

Then, centripetal force Fc = 20 kg ×  10² m/s / 4 m = 500 N

Therefore, the centripetal force on the truck is 500 N.

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Friction can be defined as a type of force that prevents two smooth surfaces from sliding together on each other. Friction is a strong force that opposes motion when two surfaces come in contact with each other.

The different methods/ways to reduce friction include;

- Application of lubricant to surfaces

- Streamlined bodies; this goes a long way in preventing friction between two bodies.

- Decrease in weight; reducing the amount of weight on a substance can also help to reduce friction

- Applying wheels to objects that move/roll on the ground.

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Answer:

12000gram

Explanation:

1kg=1000gram

so, 12kg=12x1000

12kg=12000gram

Given amount=12kg

[tex]\boxed{\sf 1kg=1000g}[/tex]

[tex]\\ \sf\longmapsto 12kg=12(1000)[/tex]

[tex]\\ \sf\longmapsto 12kg=12000g[/tex]

Answer:

an element with a small number of valence electrons and a large atomic radius

Ploughing field with harrow pulled by a tractor being a modern technology​ is true.

This involves the use of scientific knowledge to tackle different life problems and has different sectors.

Ploughing field with harrow pulled by a tractor involves machines and not manual labour which makes it a modern technology.

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We know

[tex]\boxed{\sf Momentum=Mass\times Velocity}[/tex]

[tex]\\ \sf\longmapsto Momentum=2000(20)[/tex]

[tex]\\ \sf\longmapsto Momentum=40000kgm/s[/tex]

Derived quantities depend on.( fundamental)..........physical quantity

Are you from Nepal?

Answer:

Derived quantities depend on two or more physical quantity.

Explanation:

A manometer is a device that measures air pressure using a container with a "U"-shaped tube open at one or both ends. In a closed manometer, a sample of gas is introduced into one end, which is then capped. ... This pressure represents the positive or negative difference between the gas pressure and atmospheric pressure

Answer:

2. In addition, the other end of the tube is left open to the atmosphere and it will be subjected to the pressure of approximately 1 atmosphere (atm).

3. Besides, the test pressure is greater than the pressure of 1 atm (atmosphere) the liquid in the column will be forced down by the pressure.

4. Furthermore, it will cause the liquid of the reference column to rise by an equal amount.

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:

Explanation:

Important here is to know that due north is a 90 degree angle, due east is a 0 degree angle, and due south is a 270 degree angle. Then we find the x and y components of each part of this journey using the sin and cos of the angles multiplied by each magnitude:

[tex]A_x=100cos90\\A_x=0\\B_x=55cos0\\B_x=55\\C_x=12cos270\\C_x=55[/tex]

Add them all together to get the x component of the resultant vector, V:

[tex]V_x=55[/tex]

Do the same to find the y components of the part of this journey:

[tex]A_y=100sin90\\A_y=100\\B_y=55sin0\\B_y=0\\C_y=12sin270\\C_y=-12[/tex]

Add them together to get the y component of the resultant vector, V:

[tex]V_y=88[/tex]

One thing of import to note is that both of these components are positive, so the resultant angle lies in QI.

We find the final magnitude:

[tex]V_{mag}=\sqrt{55^2+88^2}[/tex] and, rounding to 2 sig dig's as needed:

[tex]V_{mag}=[/tex] 1.0 × 10² m; now for the direction:

[tex]\theta=tan^{-1}(\frac{88}{55})=[/tex] 58°

Explanation:

If a coil of wire is placed in a changing magnetic field, a current will be induced in the wire. ... A changing magnetic field through a coil of wire therefore must induce an emf in the coil which in turn causes current to flow.

Due to the flow of the current run, the coil magnetic field is produced. Magnetic fields result in magnetic force.

The electric force between the two charges is directly propotional to the product of the charge and inversly propotional to the square of the distance between them.

A current will be generated in a wire coil if it is put in a changing magnetic field. As a result, a changing magnetic field through a coil of wire must create an emf in the coil, causing the current to flow.

A current is induced in a coil of wire when it is put in a changing magnetic field. Something generates an electric field that drives the charges around the wire, causing the current to flow.

Hence due to the flow of the current in the coil magnetic field is produced.

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Answer:

(a)Friction

Explanation:

It is due to friction as you are rubbing the glass rod with silk cloth  

as friction occurs when 2 surfaces are rubbed against each other

Therefore it is charging by friction

Answer:

According to Hook's law, we know,

strain/stress =Constant

Explanation: So, the ratio between stress and strain is always constant.

So, if stress is increased, then strain changes in that way so that this ratio always remains constant.

Answer:

I = 0.6A

Explanation:

Ohm's Law

V = I*R

I = V/R

I = 120V/200ohms

I = 0.6A

a) Her acceleration during the slide is -6.67 m/s².

b) She slides 1.03 seconds until she stops.

a) We can find her acceleration during the slide with Newton's second law:

[tex] F = ma [/tex]                        

Where:

F: is the force    

m: is the mass = 92.45 kg

a: is the acceleration =?

The force acting on the baseball player is equal to the friction force ([tex]F_{\mu}[/tex]), and it is negative because it is in the opposite direction to the motion:

[tex] -\mu N = ma [/tex]

[tex] -\mu mg = ma [/tex]

[tex] a = -\mu g [/tex]

Where:

N: is the normal force = mg

μ: is the coefficient of kinetic firction = 0.68

g: is the acceleration due to gravity = 9.81 m/s²

Hence, her acceleration during the slide is:

[tex] a = -0.68*9.81 m/s^{2} = -6.67 m/s^{2} [/tex]

b) We can calculate how long does she slide until she stops with the following kinematic equation:

[tex] v_{f} = v_{0} + at [/tex]

Where:

[tex] v_{f} [/tex]: is the final speed = 0 (when she stops)

[tex] v_{0} [/tex]: is the initial speed = 6.87 m/s

t: is the time =?

Then, the time is:

[tex] t = -\frac{v_{0}}{a} = -\frac{6.87 m/s}{-6.67 m/s^{2}} = 1.03 s [/tex]

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Answer:

necessary for the growth, development and repair of all body tissues. it's involved in many body functions, including formation of collagen, absorption of iron, the proper functioning of the immune system, wound healing, and the maintenance of cartilage, bones, and teeth.

Explanation:

Answer:

Vitamin C act as antioxidant which protect our cell from damaging caused by radicals.

El baloncesto es un deporte muy completo, que puede beneficiar mi vida al mejorar mi salud mediante el ejercicio físico, a la vez que puede mejorar el medio ambiente a través de la protección de espacios abiertos para la práctica de este y otros deportes.

El baloncesto es un deporte inventado en 1891 por James Naismith en Estados Unidos. En el, dos equipos de cinco jugadores y siete suplentes cada uno competirán entre sí. El objetivo del juego es capturar la pelota y lanzarla a través de un aro de hierro - la canasta - y evitar que el oponente haga lo mismo.

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The work done by the force on the block is:

[tex]W=135.41*3=406.23 \: J[/tex]

The direction of motion here is in the y-direction, so we need to find the component of the force in this direction.

Using trigonometric functions:

[tex]F_{y}=Fsin(37)[/tex]

This component is in the positive y-direction.

Now, there is a friction force between the block and the wall, so we need to find the friction force.

[tex]F_{f}=\mu N[/tex]

Where:

Let's use the first Newton's Law to get F.

F(y) is upward (+) and F(f) and the weight is downward (-).

[tex]F_{y}-F_{f}-W=0[/tex]

[tex]F_{y}-F_{f}=mg[/tex]

Factoring F in the left side:

[tex]F(sin(37)-\mu cos(37))=mg[/tex]    

[tex]F=\frac{mg}{sin(37)-\mu cos(37)}[/tex]  

[tex]F=\frac{5*9.81g}{sin(37)-(0.3*cos(37))}[/tex]  

[tex]F=135.41\: N[/tex]    

Therefore, the work done will be:

[tex]W=Fd[/tex]  

[tex]W=135.41*3=406.23 \: J[/tex]  

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Answer:

you didn't post any triangles. Thus, the question could not be answered.

Answer:

The given triangle is a right triangle.

The length of the hypotenuse is 2.52.5 units.

The given angle is 39\degree39° .

The unknown side xx is adjacent to the given angle.

We can therefore use the cosine function to find xx .

Recall the mnemonics CAH.

This means that;

\cos\theta=\frac{Adjacent}{Hypotenuse}cosθ=

Hypotenuse

Adjacent

This implies that,

\cos39\degree=\frac{x}{2.5}cos39°=

2.5

x

We multiply both sides by 2.52.5 to get,

2.5\cos39\degree=x2.5cos39°=x

x=2.5(0.7771)x=2.5(0.7771)

We evaluate to get

x=1.94x=1.94

Therefore the length xx of the side of the triangle is 1.91.9 units to the nearest tenth.

[tex]\boxed{\sf W=Fscos\Theta}[/tex]

[tex]\\ \sf\longmapsto W=150(50)cos 60[/tex]

[tex]\\ \sf\longmapsto W=7500\times \dfrac{1}{2}[/tex]

[tex]\\ \sf\longmapsto W=3750J[/tex]

Answer:

Here Is An OverView of What I Know About Science:

To understand what science is, just look around you. What do you see? Perhaps, your hand on the mouse, a computer screen, papers, ballpoint pens, the family cat, the sun shining through the window …. Science is, in one sense, our knowledge of all that — all the stuff that is in the universe: from the tiniest subatomic particles in a single atom of the metal in your computer's circuits, to the nuclear reactions that formed the immense ball of gas that is our sun, to the complex chemical interactions and electrical fluctuations within your own body that allow you to read and understand these words. But just as importantly, science is also a reliable process by which we learn about all that stuff in the universe. However, science is different from many other ways of learning because of the way it is done. Science relies on testing ideas with evidence gathered from the natural world. This website will help you learn more about science as a process of learning about the natural world and access the parts of science that affect your life.

Explanation:

Science helps satisfy the natural curiosity with which we are all born: why is the sky blue, how did the leopard get its spots, what is a solar eclipse? With science, we can answer such questions without resorting to magical explanations. And science can lead to technological advances, as well as helping us learn about enormously important and useful topics, such as our health, the environment, and natural hazards. Without science, the modern world would not be modern at all, and we still have much to learn. Millions of scientists all over the world are working to solve different parts of the puzzle of how the universe works, peering into its nooks and crannies, deploying their microscopes, telescopes, and other tools to unravel its secrets. I Hope This Helps.

Answer:

Physical change is a temporary change. A chemical change is a permanent change

examples of physical change are freezing of water, melting of wax, boiling of water, etc. A few examples of chemical change are digestion of food, burning of coal, rusting, etc.

HAVE A GREAT DAY :)

Answer:

Alkali metals

Explanation:

Elements in this group are highly reactive, soft, lustrous and highly conductive.

An element which is highly conductive, highly reactive, soft, and lustrous is most likely an alkali metal.

Alkali metals are in group 1 of the Periodic table which means that they have only a single valence electron.

This causes them to be soft and highly reactive because:

Examples of alkali electrons include:

In conclusion therefore, alkali metals are highly reactive and soft and so the element described above is most likely an alkali metal.

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Answer:

Normal force

Explanation:

Calculating :-

We know

[tex]\boxed{\sf F_c=\dfrac{mv^2}{r}}[/tex]

[tex]\\ \sf\longmapsto F_c=\dfrac{20(10)^2}{4}[/tex]

[tex]\\ \sf\longmapsto F_c=\dfrac{20(100)}{4}[/tex]

[tex]\\ \sf\longmapsto F_c=\dfrac{2000}{4}[/tex]

[tex]\\ \sf\longmapsto F_c=500N[/tex]

Answer:

The mass of platinum iridium rod whose diameter and height are equal an kept at international bureau of weight and measurement in Paris of France is called as one standard kg.