In order to determine causal effects between variables, researchers must use. a. Correlational designs b. Case studies O c Experimental designs O d. All of the above

Answer:

¿Podrías poner la pregunta en inglés por favor?

Explanation:

True. When light passes from a dense medium to a less dense medium, it bends away from the surface normal. This phenomenon is known as refraction.

Refraction occurs because light travels at different speeds in different media, and when it encounters a change in the optical density (refractive index) of the medium, its direction of propagation changes.

The change in direction is determined by Snell's law, which states that the angle of incidence and the angle of refraction are related to the refractive indices of the two media.

learn more about refraction from given link

https://brainly.com/question/27932095

#SPJ11

Answer:

60 J of heat are released from the system: Q=-60 J

20 J of work is done on the system: W=-20 J

∆U=Q-W

∆U=-60-(-20)

∆U=-40 J

Explanation:

If the heat is released from the system, Q should be negative.

If the heat is gained by the system, Q should be positive.

If the work is done on the system, W should be negative.

If the work is done by the system, W should be positive.

Answer:

It's true.

And this makes the state of the sun to be "plasma"

Answer: It is False.

Explanation: I am on my final test for Astronomy. And I study really hard and I know its the right answer.

When a bat flies toward a moth while the moth is flying toward the bat at speed, the bat emits a sound wave of 51.35 kHz.When a bat emits a sound wave of 51.35 kHz, the frequency of the wave detected by the bat after that wave reflects off the moth will be 51.35 kHz.

When the bat's sound wave hits the moth, the frequency of the wave will not change. However, if the moth is moving toward the bat when the sound wave hits it, the frequency of the echo will be higher than the frequency of the original sound wave that was emitted by the bat.This effect, known as the Doppler effect, is responsible for the change in frequency of a wave due to the relative motion between the source of the wave and the observer. In this case, the frequency of the wave detected by the bat after it reflects off the moth will be slightly higher than the original frequency of 51.35 kHz, due to the fact that the moth is moving toward the bat at speed.As for the requested word count, this answer has a total of 131 words.

To know more about frequency visit:

https://brainly.com/question/29739263

#SPJ11

Answer:

Every object on the surface of the earth is pulled towards its surface because of a force known as the gravitational force. It is a force of attraction that exists between any two objects with mass.

The gravitational force of the earth pulls every object towards the surface of the earth. Because of this, an object free in the air is accelerated. The acceleration caused by the gravitational force is known as the acceleration due to gravity.

The magnitude of the acceleration is constant in a downward direction.

Acceleration is the rate of change in velocity.

Learn more about acceleration here:-https://brainly.com/question/460763

#SPJ2

The moment of inertia of an ice skater spinning in place is a measure of the skater's resistance to changes in her rotational motion.

The moment of inertia depends on  distribution of  skater's mass and the distance of that mass from the axis of rotation. When the skater extends her arms out to both sides, her moment of inertia increases because the mass is distributed farther from her axis of rotation. Conversely, when she brings her arms in close to her body, her moment of inertia decreases because the mass is distributed closer to her axis of rotation. Therefore, the correct statement is that the moment of inertia is larger when her arms are further from her axis of rotation.

To know more about moment of inertia, here

brainly.com/question/15246709

#SPJ4

The magnitudes of the accelerations of the two carts are equal.

Two carts are labeled A and B, and each cart is moving with constant acceleration. The velocities of each cart are measured at a start time t1 and a finish time t2 (same start and finish time for both carts). The magnitudes of the accelerations of two carts are the same. According to the given diagram, it is observed that the direction of velocity in both carts is in the same direction. The magnitudes of the velocity for Cart A and Cart B at time t2 are the same.

Therefore, the magnitudes of the accelerations of both carts will be the same, and the direction of acceleration will be the same as the direction of velocity.

Here you can learn more about the accelerations

https://brainly.com/question/980919#

#SPJ11

flat disk like shape

________________

o0o0o0o0o0o0o0o0

The electric field strength inside a copper wire can be calculated using the formula E = J/σ, where J is the current density and σ is the electrical conductivity of copper. In this case, the current density can be calculated as J = I/A, where I is the current and A is the cross-sectional area of the wire.

Given that the diameter of the wire is 1.2 mm, its radius is 0.6 mm or 0.0006 m.

Thus, the cross-sectional area is A = πr^2 = 3.14 x (0.0006)^2 = 1.13 x 10^-6 m^2.

Therefore, the current density is J = 20/1.13 x 10^-6 = 1.77 x 10^7 A/m^2. Using the electrical conductivity of copper, which is 5.96 x 10^7 S/m, the electric field strength inside the wire can be calculated as E = J/σ = 1.77 x 10^7/5.96 x 10^7 = 0.296 V/m.

To Learn more about copper  Click this!

brainly.com/question/14378468

#SPJ11

Answer:

I think its O A. True.

The direction of the skaters after the collision is 61 degrees.

The momentum of the skaters is calculated as follows;

P(N) = 58.9 x 7.8 = 459.42 kgm/s

P(E) = 72.6 x 3.5 = 254.1 kgm/s

The direction of the skaters after the collision is calculated as follows;

\(\theta = tan^{-1} (\frac{459.42}{254.1} )\\\\\theta = 61^ 0\)

Thus, the direction of the skaters after the collision is 61 degrees.

Learn more about direction of collision here: https://brainly.com/question/25891473

Answer:

A) Sue is lifting the bucket by a force of 49.035 newtons.

B) The bucket has an acceleration of 8.207 meters per square second on the Moon.

Explanation:

A) According to the First Newton's Law, a system is at equilibrium when it is either at rest or travelling at constant velocity. In this case, Sue must exert an external force on the bucket, whose magnitude is equal to the weight of the bucket but direction is opposed to it. By Second Newton's Law, we find that:

\(\Sigma F = F - m\cdot g = 0\) (1)

Where:

\(F\) - Lifting force, measured in newtons.

\(m\) - Mass of the bucket, measured in kilograms.

\(g\) - Gravitational acceleration, measured in meters per square second.

If we know that \(m = 5\,kg\) and \(g = 9.807\,\frac{m}{s^{2}}\), then the lifting force is:

\(F = m\cdot g\)

\(F = (5\,kg)\cdot \left(9.807\,\frac{m}{s^{2}} \right)\)

\(F = 49.035\,N\)

Sue is lifting the bucket by a force of 49.035 newtons.

B) By the Second Newton's Law, we have the following model:

\(\Sigma F = F-m\cdot g = m\cdot a\) (2)

Where \(a\) is the net acceleration of the bucket, measured in meters per square second.

If we know that \(F = 49.035\,N\), \(m = 5\,kg\) and \(g = 1.6\,\frac{m}{s^{2}}\), then the net acceleration of the bucket is:

\(a = \frac{F}{m} -g\)

\(a = \frac{49.035\,N}{5\,kg}-1.6\,\frac{m}{s^{2}}\)

\(a = 8.207\,\frac{m}{s^{2}}\)

The bucket has an acceleration of 8.207 meters per square second on the Moon.

(a) The force applied by Sue in lifting the bucket at a constant velocity is 49 N.

(b) The acceleration of the bucket when lifted on the moon is 8.2 m/s².

The given parameters;

The force applied by Sue in lifting the bucket at a constant velocity is calculated as;

\(F = m(a + g)\)

\(F= mg\\\\F = 5 \times 9.8\\\\F = 49 \ N\)

The acceleration of the bucket when lifted on the moon with the calculated force is;

\(F = m(a + g)\\\\a+g = \frac{F}{m} \\\\a = \frac{F}{m} - g\\\\a = \frac{49}{5} - 1.6\\\\a = 8.2 \ m/s^2\)

Learn more here:https://brainly.com/question/1685393

Given :

Velocity of bullet, \(v_b=300\ m/s\).

Mass of bullet, m = 0.005 kg.

Mass of rifle, M = 5 kg.

To Find :

The recoil velocity of the rifle.

Solution :

Since, their is no external force is acting.

So, momentum of the system will be conserved :

Initial momentum = Final momentum

m(0) + M(0) = m(300) + Mv

\(v=-\dfrac{300m}{M}\\\\v=-\dfrac{300\times 0.005}{5}\\\\v=-0.3 \ m/s\)

Therefore, recoil velocity of the rifle is 0.3 m/s.

Hence, this is the required solution.

The repulsion force between the two Arkon nuclei when the distance between them is 1x10⁻³μm is approximately 7.4x10⁻¹⁴N. The correct option is d. 7.4x10⁻¹⁴N.

The formula for repulsion force between two Arkon nuclei when the distance between them is given by Coulomb's law. Coulomb's law states that the force between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. Mathematically, the law can be expressed as F=kq1q2/r²,

Where F is the force, q1 and q2 are the charges, r is the distance between the charges, and k is the Coulomb's constant.The electric charge of one electron is 1.6x10⁻¹⁹C.

Therefore, the charge of the Arkon nucleus with 18 protons = 18(1.6x10⁻¹⁹) C = 2.88x10⁻₈⁸ CThe force between the two Arkon nuclei can be calculated using the formula above.

F=kq1q2/r²

Substituting the values we have;F = (9x10⁹)(2.88x10⁻¹⁸ C)2/(1x10⁻³ m)2F ≈ 7.4x10⁻¹⁴ N. Therefore, the repulsion force between the two Arkon nuclei when the distance between them is 1x10-3μm is approximately 7.4x10⁻¹⁴N. The correct option is d. 7.4x10⁻¹⁴N.

Learn more about repulsion force:

https://brainly.com/question/28439369

#SPJ11

Answer:

The reaction absorbs energy from its surroundings.

Explanation:

An endothermic reaction is any reaction in which energy is absorbed by the reaction system.Thus implies that energy is withdrawn from the environment A cold pack's function is based on an endothermic chemical reaction.

The absorption of energy by the reaction system means that the environment feels cool in an endothermic reaction.This manifests in a decrease in the temperature of the cold pack.

The required magnitude of the force that stopped Melissa's car is 118608.7 N.

According to the first law, unless a force acts on an object, it will not alter its motion. According to the second law, an object's force is determined by multiplying its mass by its acceleration. According to the third law, when two objects interact, they exert equal-sized and opposite-direction forces upon one another.

An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force.

Given,

speed=8.133 m/s

final velocity=0 (due to impact)

time=0.3994 seconds

distance=11.01m

Then,

S = ut + (at^2)/2

a = 2(s - ut)t^2

a = 97.3 m/s^2

So,

Force = ma

Force = 1219(97.3)

Force = 118608.7 N

To know more about acceleration visit:-

brainly.com/question/12550364

#SPJ4

On the moon you weigh 6 times lighter so for this problem you multiply 140n by 6.

Your weight on the Moon is 16.5% what you would experience on Earth. In other words, if you weighed 100 kg on Earth, you would weigh a mere 16.5 kg on the Moon. For you imperial folks, imagine you tipped the scales at 200 pounds.

It’s because of the lower gravity on the Moon. Objects on the surface of the Moon experience only 16.5% of the gravity they would experience on Earth.

The mass of the Moon is only 1.2% the mass of the Earth, so you might expect it to have only 1.2% of the gravity. But it’s only 27% of the size of the Earth, so when you’re standing on the surface of the Moon, you’re much closer to its center of gravity.

Therefore, On the moon you weigh 6 times lighter so for this problem you multiply 140n by 6.

To learn more about Gravity, refer to the link:

https://brainly.com/question/4014727

#SPJ1

The acceleration of the scooter is 2.5 m/s².

To find the acceleration of the scooter, we can use the formula:

acceleration (a) = change in velocity (Δv) / time (t)

Given:

Initial velocity (u) = 10 m/s

Final velocity (v) = 20 m/s

Time (t) = 4 sec

Using the formula, we can calculate the change in velocity:

Δv = v - u

    = 20 m/s - 10 m/s

    = 10 m/s

Now, substitute the values into the acceleration formula:

a = Δv / t

  = 10 m/s / 4 sec

  = 2.5 m/s²

Learn  more about acceleration here:-

https://brainly.com/question/2303856

#SPJ11

The potential energy of the 417000 kg ISS (space station) at an altitude of 400.0 km can be calculated as follows: Potential energy is the energy possessed by a body by virtue of its position or state.

The potential energy of a body of mass m at a height h above the ground is given by the formula: Potential energy = mgh where m is the mass of the body, g is the acceleration due to gravity, and h is the height of the body above the ground. In this case, the mass of the ISS is given as 417000 kg, and its altitude is given as 400.0 km. We need to convert the altitude to meters before we can substitute the values in the formula.

1 km = 1000 m Therefore, 400.0 km

= 400.0 × 1000 m

= 4.00 × 10⁵ m Substituting the values in the formula: Potential energy = mgh= 417000 × 9.81 × 4.00 × 10⁵

= 1.64 × 10¹³ J

Therefore, the potential energy of the 417000 kg ISS (space station) at an altitude of 400.0 km is 1.64 × 10¹³ J. Potential energy is the energy possessed by a body by virtue of its position or state. It is defined as the work done in lifting a body to a certain height above the ground.

To know more about potential energy visit:

https://brainly.com/question/24284560

#SPJ11

Given that,

Frequency = 100 Hz

Velocity = 20 m/s

Suppose, Determinar la diferencia de  frecuencia entre la onda que recibe el observador directamente de la sirena y la onda que le llega reflejada  en el acantilado.

We need to calculate the frequency heard by the observer directly from source

Using formula of frequency

\(f_{1}=f\times(\dfrac{v}{v-v_{s}})\)

Where, v = speed of sound

\(v_{s}\) = speed of source

f = frequency of source

Put the value into the formula

\(f_{1}=100\times\dfrac{340}{340-20}\)

\(f_{1}=106.25\ Hz\)

We need to calculate the frequency heard by the observer coming after reflection from cliff

Using formula of frequency

\(f_{2}=f\times(\dfrac{v}{v+v_{s}})\)

Put the value into the formula

\(f_{2}=100\times\dfrac{340}{340+20}\)

\(f_{2}=94.4\ Hz\)

We need to calculate the difference of  frequency

Using formula for difference of  frequency

\(\Delta f=f_{1}-f_{2}\)

Put the value into the formula

\(\Delta f=106.25-94.4\)

\(\Delta f=11.85\ Hz\)

Hence, The difference of frequency is 11.85 Hz.

The period of oscillation of a spider hanging on a silk thread, tapped once every second, is one second.

What is the period of oscillation of a spider hanging on a silk thread when tapped once every second?

The time it takes for one complete up-and-down motion of the spider on the silk thread is called the period of oscillation, denoted by T. We know from the problem statement that the spider has the largest amplitude on its bungee cord when tapped exactly once every second.

If the tapping is done exactly once every second, then the spider is experiencing a periodic force with a frequency of 1 Hz. In this case, the period of oscillation T is equal to the reciprocal of the frequency, which is:

T = 1/f = 1/1 Hz = 1 second

Therefore, the spider completes one full oscillation (i.e., up-and-down motion) every second.

To learn more about period of oscillation, visit: https://brainly.com/question/22499336

#SPJ4

The graph shown in the first option nicely plots the lion's and gazelle's velocities as a function of time, so option A is the correct answer.

Velocity is the rate of change of displacement over time.

As mentioned in the problem of running at a constant speed towards a gazelle with a standing lion as shown above.

So option A is correct.

To know more about velocities,

https://brainly.com/question/13471585

#SPJ4

Answer:

To find the work done in moving the particle from the origin to x = 2, we need to integrate the force over the given interval.

The work done (W) is calculated by integrating the force function with respect to displacement (dx) from the initial position (0) to the final position (2):

W = ∫(0 to 2) (10x³ - 5) dx

Integrating the force function, we get:

W = ∫(0 to 2) (10x³ - 5) dx = [2.5x⁴ - 5x] evaluated from 0 to 2

Now, substituting the upper limit (2) and lower limit (0) into the equation:

W = [2.5(2)⁴ - 5(2)] - [2.5(0)⁴ - 5(0)]

 = [2.5(16) - 10] - [0 - 0]

 = 40 - 10

 = 30

Therefore, the work done in moving the particle from the origin to x = 2 is 30 units of work.

Explanation:

Answer:

Explanation:

Remark

The only thing that might trip you up is what to do with the angle. The vertical component of the 15 degrees does no work against anything. So the 15 degrees limits the horizontal force.

The formula is

Work = F * d * cos(15)

The givens are

F = 2000 N

d = 30 m

Cos(15) = 0.9659

Solution

Work = 2000 * 30 * cos(15)

Work = 57,955

Rounded to two places would be 5.8 * 10^4

C

Answer:

C

Explanation:

because cooling down makes your blood flow through your body much easier and fatser.

Answer:

C.It keeps your blood flowing evenly.

Explanation:

When copper sulfate is dissolved in water, the solution produced is saturated.

When the solute added over and over is no more able to dissolve, the solution formed is saturated.

For a certain amount of solvent, temperature and pressure, the solute is unable to dissolve and precipitate or from crystals. This condition is best termed as the saturated solution. So, the solvent can not dissolve any more solute.

Thus, the solution produced is saturated.

Learn more about saturated solution.

https://brainly.com/question/1851822

#SPJ2

Answer:

it would be nine

Explanation:

just subtract 8 from 17