A roller coaster has a vertical loop with radius 25.7 m. With what minimum speed should the roller-coaster car be moving at the top of
the loop so that the passengers do not lose contact with the seats?
m/s

Answer:

you should provide the options for us to answer?

Answer:

h> 2R

Explanation:

For this exercise let's use the conservation of energy relations

starting point. Before releasing the ball

       Em₀ = U = m g h

Final point. In the highest part of the loop

       Em_f = K + U = ½ m v² + ½ I w² + m g (2R)

where R is the radius of the curl, we are considering the ball as a point body.

      I = m R²

      v = w R

we substitute

       Em_f = ½ m v² + ½ m R² (v/R) ² + 2 m g R

       em_f = m v² + 2 m g R

Energy is conserved

       Emo = Em_f

       mgh = m v² + 2m g R

       h = v² / g + 2R

The lowest velocity that the ball can have at the top of the loop is v> 0

      h> 2R

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:

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

Answer:

none of those are right, its technically 96.5%. so i would say 97% is your best bet because thats closest and it just rounds up :)

Explanation:

In the historical sense, postmodern society is simply a society that occurs after the modern society. ... Many of the elements of a society like this are reactions to what the modern society stood for: industrialism, rapid urban expansion, and rejection of many past principles.

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:

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.

Learn more about index of refraction.

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#SPJ2

Wave-D (the red one) has the smallest amplitude of the 4 waves on this graph.

Answer:

Current

I think The choose (B)

B. Electric current

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:

 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:

Distance traveled = 3 * 10E8 * 17.2 * 10E-9 = 5.16 m

.81 / 3 * 10E8 = 2.7 * 10E-9    normal time thru glass

(20.8 - 17.2) * E10-9 = 3.6 * 10E-9   additional time due to glass

c tg = c n ta      where tg and ta are the times spent in glass and air

(Note you can also write Va = n Vg  or  D / ta = n D / tg)

n = tg / ta = 3.6 / 2.7 = 1.33 the index of refraction of the glass

Wavelength (air) = Wavelength (glass) * n

Wavelenght = 560 nm / 1.33 = 421 nm

Answer:

B. [tex]30\,s\,< t \le 40\,s[/tex].

Explanation:

The vehicle is travelling eastwards when its velocity is positive and westwards when velocity is negative. According to the graph, [tex]v > 0[/tex] for [tex]30\,s\,< t \le 40\,s[/tex]. Hence, correct answer is B.

Answer:

I hope this will help you. i tried my best

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:

3.75 watts

Explanation:

power = volts * current

2.5 * 1.5 =

3.75

Answer:

Explanation:

Let the stretch produced in first spring and second spring be x₁ and x₂ respectively. 300 N is the restoring force created in them .

k₁x₁ = k₂x₂ = 300 N .

k₁ = 11000 N/m

11000 x₁ = 300N

x₁ = 300 N / 11000

= 0.027 m

= 2.7 cm .

Direct relation is present between distance and time which means one has direct impact on the value of other.

There is direct relationship between distance and time. Direct relation means if one increases the other automatically increases while on the other hand, if one decreases the other will also decreases. If there is a large amount of distance so more time is required to pass it while on the other hand, if there is less distance so less time is required to complete it so we can conclude that there is direct relationship between distance and time.

https://brainly.com/question/24323600

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:

[tex]T=346.5N[/tex]

Explanation:

From the question we are told that:

Density [tex]\rho= (1.44 * 10^{-2} kg/m)[/tex]

Frequency[tex]F=93.0Hz[/tex]

Length[tex]l=0.834m[/tex]

Generally the equation for Frequency is mathematically given by

[tex]F=\frac{1}{2 l}sqrt{\frac{T}{\rho}}[/tex]

Therefore

[tex]T=\rho(2 lF)^2[/tex]

[tex]T= (1.44 * 10^{-2}*(2*0.834)(93.0))^2[/tex]

[tex]T=346.5N[/tex]

Answer:

The frictional force between two bodies depends mainly on three factors: (I) the adhesion between body surfaces (ii) roughness of the surface (iii) deformation of bodies

Answer:

They sound tinkling in solid hard like metal.

They can vibrate soft surface

I could just Ans this

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:

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.

Explanation:

The absolute threshold of hearing is the minimum sound level of a pure tone that an average human ear with normal hearing can hear with no other sound present. The absolute threshold relates to the sound that can just be heard by the organism.

Answer:

B

Explanation:

ABSORPTION

Answer: c. 40m

Explanation:

See picture

Answer:

0.028 M.

Explanation:

NOTE: This question is a chemistry question. However, the answer to the question can be obtained as shown below:

We'll begin by calculating the number of mole in 2.52 g of oxalic acid, C₂H₂O₄. This can be obtained as follow:

Mass of C₂H₂O₄ = 2.52 g

Molar mass of C₂H₂O₄ = (2×12) + (2×1) + (4×16)

= 24 + 2 + 64

= 90 g/mol

Mole of C₂H₂O₄ =?

Mole = mass / molar mass

Mole of C₂H₂O₄ = 2.52 / 90

Mole of C₂H₂O₄ = 0.028 mole

Finally, we shall determine the molarity of the solution. This can be obtained as follow:

Mole of C₂H₂O₄ = 0.028 mole

Volume = 1 L

Molarity =?

Molarity = mole / Volume

Molarity = 0.028 / 1

Molarity = 0.028 M

Therefore, the molarity of the solution is 0.028 M.