Give examples of motion in which the directions of the velocity and acceleration vectors are (a) opposite, (b) the same, and (c) mutually perpendicular​

Answer:

A denser object will usually have a high index of

refraction.

A denser object will usually have a high index of refraction.

The refractive index is the ratio of the speed of light in vacuum and speed of light in any medium.

n = c/v

The density is greater for the denser medium (water, oil, mercury, etc) then the rarer medium (any gas or air).

When a light ray travels through denser medium, its velocity is reduced and the refracted ray bends towards normal.

As, the index of refraction is inversely proportional to the velocity of light in the medium, index of refraction will be high for denser object.

Thus, denser object have high index of refraction.

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Answer: c. 40m

Explanation:

See picture

option a ...

please mark hcfhvx

Answer:

Alternating current at which when entered into the loop cause it to magnetize

Answer:

Final kinetic energies of both astronauts will be the same.

Explanation:

If we ignore all the friction present between the ramp and the person. Then essentially there is no loss of energy in the system. Hence the initial potential energies of the astronauts must be equal to their final kinetic energies.

Now the potential energy depends upon mass, height and acceleration due to gravity. All these parameters for both the astronauts. Therefore,both astronauts have same initial potential energies.

Similarly, the final kinetic energies of astronauts will also be the same.

When solving question that contains equations and the use mathematical computations, It is always ideal to list the parameters given.

Now, given that:

Assumptions:

∴

For a motion under constant acceleration, we can apply the kinematic equation:

[tex]\mathsf{v^2 = u^2 + 2as}[/tex]

where;

From the above equation, making acceleration (a) the subject of the formula:

[tex]\mathsf{v^2 - u^2 =2as }[/tex]

[tex]\mathsf{a = \dfrac{v^2 - u^2 }{2s}}[/tex]

The initial velocity (u) is given in km/h, and we need to convert it to m/s as it has an effect on the unit of the acceleration.

since 1 km/h = 0.2778 m/s

100 km/h = 27.78 m/s

[tex]\mathsf{a = \dfrac{(0)^2 - (27.78)^2 }{2(1)}}[/tex]

[tex]\mathsf{a = \dfrac{- 771.7284 }{2}}[/tex]

a = - 385.86 m/s²

Similarly, from the kinematic equation of motion, the formula showing the relation between time, acceleration, and velocity is;

v = u + at

where;

v = 0

-u = at

[tex]\mathsf{t = \dfrac{-u}{a}}[/tex]

[tex]\mathsf{t = \dfrac{-27.78}{-385.86}}[/tex]

t = 0.07 seconds

An airbag is designed in such a way as to prevent the driver from hitting on the steering wheel or other hard substance that could damage the part of the body. The use of the seat belt is to keep the driver in shape and in a balanced position against the expansion that occurred by the airbag during the collision on the brick wall.

Thus, we can conclude that in order to estimate how fast the airbag must inflate to effectively protect the driver, the airbag must be inflated at 0.07 seconds faster before the collision to effectively protect the driver.

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Answer:

Hence the square root of the wavelength. What is the wavelength of 27 MHz radio waves  11 m; option A is the correct answer.

Hence, as the frequency of the radio waves increases the penetration depth decreases.

Option C is the correct answer.

Hence the electric field amplitude has decreased by a factor of √3.

Hence the correct option is D.

Explanation:

[tex]c=n\lambda[/tex], where the symbols have their usual meanings.

[tex]\lambda =c/n\\= 3\times10^{8}/27\times10^{6}\\\\=11.11 m[/tex]

Hence, wavelength = 11 m; option A is the correct answer.

As given that, the penetration depth is proportional to the square root of wavelength, and we know that,

wavelength and frequency are inversely proportional to each other.

Hence, as the frequency of the radio waves increases the penetration depth decreases.

Option C is the correct answer.

Electric field amplitude is directly proportional to the square root of the intensity. Therefore, the ratio between the electric field amplitude is,

[tex]\frac{E\sigma_{1} }{E\sigma_{2} } =\sqrt{\frac{I_{1} }{I_{2} } }[/tex]

Here to find the ratio of intensities,

[tex]{\frac{I_{1} }{I_{2} } } = 3[/tex]

Therefore,

[tex]\frac{E\sigma_{1} }{E\sigma_{2} } =\sqrt{3 }[/tex]

Hence the correct option is D.

Answer:

60 deg from Y-axis is 150 deg from X-axis

x = L cos theta = 23,2 cos 150 = -.867 * 23.2 = -20.1

Answer:

24 meters

Explanation:

Find the final velocity. 12m/s

d=[final-initial]/2×time

D=(6m/s)×4=24 m/s

Answer:

you should provide the options for us to answer?

Answer:

4.926 L Y 7.389 L

Explanation:

first you calculate the tank volume

V = π[tex](14 cm)^{2}[/tex](10 cm = [tex]12315 cm^{3}[/tex]

then you convert to liters

[tex]12315 cm^{3}[/tex] = 12.315 l

then you calculate the liters of water

2/5(12.35 l) = 4.926 l

finally we calculate the amount without water

12.315 l - 4.926 l = 7.389 l

HERE IS MORE INFORMATION ON THE SUBJECT. THEY REMOVED THE

ENGLISH SITE BUT YOU CAN USE TRANSLATOR

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Answer:

a)  [tex]d_g=1.95m[/tex]

b) [tex]d_g'=2.3m[/tex]

Explanation:

From the question we are told that:

Depth [tex]d=2.60[/tex]

a)

Generally the equation for distance to ground is mathematically given by

[tex]\frac{d_g}{d}=\frac{1}{n}[/tex]

Where

[tex]n=\frac{4}{3}[/tex]

Therefore

[tex]d_g=\frac{d}{n}[/tex]

[tex]d_g=\frac{2.6}{4/3}[/tex]

[tex]d_g=1.95m[/tex]

b)

For when The pool is filled halfway with water

[tex]\frac{d_g}{d}=\frac{1}{n}[/tex]

[tex]d_g'=\frac{1.3}{4/3}[/tex]

[tex]d_g'=0.98m[/tex]

Therefore

[tex]d_g'=(1.3+0.98)[/tex]

[tex]d_g'=2.3m[/tex]

Complete Question

A charged particle of mass 0.0040 kg is subjected to a 40-T magnetic field which acts at a right angle to its motion. If the particle moves in a circle of radius 0.10 m at a speed of 20m/s, what is the magnitude of the charge on the particle?

Answer:

[tex]q=0.020C[/tex]

Explanation:

From the question we are told that:

Mass [tex]m=0.004kg[/tex]

Magnetic field [tex]B=40-T[/tex]

Radius [tex]r=0.10m[/tex]

Speed [tex]v= 20m/s[/tex]

Generally the equation for Radius of a circular path is mathematically given by

[tex]r=\frac{p}{qB}[/tex]

Where

[tex]p=mv[/tex]

Therefore

[tex]q=\frac{mv}{rB}[/tex]

[tex]q=\frac{0.004kg*20m/s}{0.1*40}[/tex]

[tex]q=0.020C[/tex]

Answer:

Explanation:

[tex]w_f^2=w_o^2-2\alpha\theta\\\\0=w_o^2-2\alpha\theta\\\\\theta={w_o^2\over{2\alpha}}[/tex]

[tex]w_o=2\pif=2\pi*8Hz=16\pi{rad\over{s}}\\\\\alpha=2.2{rad\over{s^2}}\\\\\theta={(16\pi{rad\over{s}})^2\over{2*2.2{rad\over{s^2}}}}=574.23rad[/tex]

[tex]revolutions={\theta\over{2\pi}}={574.23\over{2\pi}}=91.39[/tex]

Answer:

        x = 240 m

Explanation:

This is a kinematics exercise

Let's fix our frame of reference on car A

           x = x₀ₐ+ v₀ₐ t + ½ aₐ t²

the initial position of car a is zero

           x = 0 + v₀ₐ t + ½ 0.8 t²

for car B

          x = x_{ob} + v_{ob} t - ½ a_b t²

car B's starting position is 30 m

         x = 30 + v_{ob} t - ½ 0.4 t²

at the point where they meet, the position of the two vehicles is the same

         0 + v₀ₐ t + ½ 0.8 t² = 30 + v_{ob} t - ½ 0.4 t²

let's reduce the speeds to the SI system

        v₀ₐ = 14.4 km / h (1000 m / 1 km) (1h / 3600s) = 4 m / s

        v_{ob} = 23.4 km / h = 6.5 m / s

        4 t + 0.4 t² = 30 + 6.5 t - 0.2 t²

        0.2 t² - 2.5 t - 30 = 0

        t² - 12.5 t - 150 = 0

we solve the quadratic equation

       t = [tex]\frac{12.5 \pm \sqrt{12.5^2 + 4 \ 150} }{2}[/tex]

       t = [tex]\frac{12.5 \ \pm 27.5}{2}[/tex]

       t₁ = 20 s

       t₂ = -7.5 s

time must be a positive quantity so the correct result is t = 20 s

let's look for the distance

        x = 4 t + ½ 0.8 t²

        x = 4 20 + ½ 0.8 20²

        x = 240 m

Answer:

Yes

Explanation:

A scientific theory is an explanation of a natural phenomenon based on available facts. If an Astrophysicist (a scientist who studies the universe and its celestial constituents) performs several successful experiments about a natural body like the sun and tests the results of his experiment using the principles of maths and physics and they come out as true, then he can propose a scientific theory based on his findings.

Unlike a scientific law that simply states a fact, a scientific theory provides evidence and explanation to support the facts.

Answer:

 E = [tex]\frac{Q}{L^2 \epsilon_o}[/tex]

Explanation:

For this exercise we use that the electric field is a vector, so the resulting field is

          E_total = E₁ + E₂                      (1)

since the field has the same direction in the space between the planes

Let's use Gauss's law for the electric field of each plate

Let's use a Gaussian surface that is a cylinder with the base parallel to the plate, therefore the normal to the surface and the field lines are parallel and the angle is zero so cos 0 = 1

          Ф  = ∫ .dA = [tex]q_{int}[/tex] /ε₀

if we assume that the charge is uniformly distributed on the plate we can define a charge density

         σ = q_{int} A

as the field exists on both sides of the plate on the inside

          E A = A σ / 2ε₀

          E = σ / 2ε₀

we substitute in equation 1

         E = σ /ε₀

for the complete plate

         σ = Q / A = Q / L²

we substitute

         E = [tex]\frac{Q}{L^2 \epsilon_o}[/tex]

ANSWER; KE=5mv^2 so it is proportional to v^2.

Explanation:So if you triple the velocity you are replacing v with 3v. Then you get (3v)^2=9v^2.

Answer:

The car will make the turn perfectly

Explanation:

Given that the centripetal force= mv^2/r

M= mass of the car

v = speed of the car

r= radius

Hence;

F = 1000 × (14)^2/50

F= 3920 N

The frictional force = μmg

μ = coefficient of static friction

m= mass

g = acceleration due to gravity

Frictional force= 0.6 × 1000× 10

Frictional force = 6000 N

The car will not skid off the curve because the frictional force is greater than the centripetal force.

Answer:

The density at 300 C is [tex]2641.68 kg/m^3[/tex].

Explanation:

density at 0 degree, d = 2700 kg/m3

coefficient of linear expansion, = 24 x 10^{-6} /K

Let the density at 300 C is d'.

Use the formula of the cubical expansion

[tex]d'= d (1-3\alpha \Delta T)\\\\d'= 2700(1- 3 \times 24\times 10^{-6}\times 300)\\\\d' = 2641.68 kg/m^3[/tex]

Answer: When a pathogen enters their colony, ants change their behavior to avoid the outbreak of disease. In this way, they protect the queen, brood and young workers from becoming ill. These results, from a study carried out in collaboration between the groups of Sylvia Cremer at the Institute of Science and Technology Austria (IST Austria) and of Laurent Keller at the University of Lausanne, are published today in the journal Science.

Explanation: search for it.

Answer:

No

Explanation:

You could try to give it enough to fill all valence electrons in all of the atoms in the conductor, but practically this could not be achieved.

Answer:

The electric potential energy is 6.72 x 10^-11 J.

Explanation:

Potential difference, V = 4.2 x 10^8 V

charge of electron, q = - 1.6 x 10^-19 C

Let the potential energy is U.

U = q V

U = 1.6 x 10^-19 x 4.2 x 10^8

U = 6.72 x 10^-11 J

Answer:

Current

I think The choose (B)

B. Electric current

Answer:

3.75 watts

Explanation:

power = volts * current

2.5 * 1.5 =

3.75

Answer:

 f = v / 4L

the frequency of the instruments is reduced by the decrease in the speed of the wave with the temperature.

Explanation:

In wind instruments the wave speed must meet

          v = λ f

          λ = v / f

from v is the speed of sound that depends on the temperature

          v = v₀ [tex]\sqrt{1+ \frac{T [C]}{273} }[/tex]

where I saw the speed of sound at 0ºC v₀ = 331 m/s  the temperature is in degrees centigrade, we can take the degrees Fahrenheit to centigrade with the relation

            (F -32) 5/9 = C

            76ºF = 24.4ºC

            45ºF = 7.2ºC

With this relationship we can see that the speed of sound is significantly reduced when leaving the house to the outside

at T₁ = 24ºC               v₁ = 342.9 m / s

at T₂ = 7ºC                 v₂ = 339.7 m / s

To satisfy this speed the wavelength of the sound must be reduced, so the resonant frequencies change

              λ / 4 = L

              λ= 4L

              v / f = 4L

              f = v / 4L

Therefore, the frequency of the instruments is reduced by the decrease in the speed of the wave with the temperature.

Answer:

B

Explanation:

ABSORPTION

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The answer is...

C. Work and time.

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Answer:

[tex]H=1.35m[/tex]

Explanation:

From the question we are told that:

Height [tex]h=1.8m[/tex]

Depth of Water [tex]d=3.0m[/tex]

Where

Refraction index of water [tex]n = 4 / 3[/tex]

Generally the equation for Apparent height of the diver  is mathematically given by

[tex]H=h\frac{h}{n}[/tex]

[tex]H=\frac{1.8}{\frac{4}{3}}[/tex]

[tex]H=1.35m[/tex]