A sample of silver (with work function Φ=4.52 eV ) is exposed to an ultraviolet light source (????=200 nm), which results in the ejection of photoelectrons. What changes will be observed if:

1. The silver is replaced with copper (Φ= 5.10 eV)?

a. more energetic photoelectrons (on average)
b. no photoelectrons are emitted more photoelectrons ejected
c. less energetic photoelectrons (on average)
d. fewer photoelectrons ejected

2. A second (identical) light source also shines on the metal?

a. fewer photoelectrons ejected
b. no photoelectrons are emitted more
c. energetic photoelectrons (on average)
d. less energetic photoelectrons (on average)
e. more photoelectrons ejected


3. The ultraviolet source is replaced with an X-ray source that emits the same number of photons per unit time as the original ultraviolet source?

a. no photoelectrons are emitted
b. less energetic photoelectrons (on average)
c. fewer photoelectrons ejected
d. more energetic photoelectrons (on average)
e. more photoelectrons ejected

Answer:

The image height is 3.0 cm

Explanation:

Given;

object distance, \(d_o\) = 15.0 cm

image distance, \(d_i\) = 5.0 cm

height of the object, \(h_o\) = 9.0 cm

height of the image, \(h_i\) = ?

Apply lens equation;

\(\frac{h_i}{h_o} = -\frac{d_i}{d_o}\\\\ h_i = h_o(-\frac{d_i}{d_o})\\\\h_i = -9(\frac{5}{15} )\\\\h_i = -3 \ cm\)

Therefore, the image height is 3.0 cm. The negative values for image height indicate that the image is an inverted image.

Answer:

neutrons protons electrons

Explanation:

after the Big Bang, the universe was filled with neutrons, protons, electrons, anti-electrons, photons and neutrinos.

Answer:

Explanation:

To find the mass of an object given it's acceleration and the force acting on it we use the formula

\(mass = \frac{force}{acceleration} \\ \)

From the question

force = 500 N

acceleration = 5.0 m/s²

We have

\(mass = \frac{500}{5} \\ \)

We have the final answer as

Hope this helps you

The correct answer is B. Observations had led to the belief that the Sun, Moon, and stars revolved around Earth.

The geocentric model, which placed Earth at the center of the universe with the Sun, Moon, and stars revolving around it, was widely accepted until the 16th century for several reasons. One of the primary reasons was that observations seemed to support this view. For example, it was observed that the stars appeared to move across the sky in a circular path, and it was assumed that this was due to their motion around Earth. Similarly, the Sun and Moon appeared to rise and set each day, which was consistent with their motion around Earth.

The geocentric model was consistent with the prevailing philosophical and religious beliefs of the time, which held that Earth was a special and unique place at the center of the universe. It was not until the development of the heliocentric model, which placed the Sun at the center of the solar system, and the refinement of astronomical observations, that the geocentric model was gradually abandoned.
The correct option is B. Observations had led to the belief that the Sun, Moon, and stars revolved around Earth.

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The magnitude of the force and the impulse applied to the car are  85714 N and  30000 N-s respectively.

The definition of force in physics is: The push or pull on a massed object changes its velocity. An external force is an agent that has the power to alter the resting or moving condition of a body. It has a direction and a magnitude.

The magnitude of the force applied to the car = change in momentum/time interval

= (1200 kg × 25 m/s - 1200 kg×0)/0.35 second

= 85714 N.

The impulse applied to the car = change in momentum

= (1200 kg × 25 m/s - 1200 kg×0)

= 30000 N-s.

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The relationship between distance, time, mass, velocity, and momentum is p = m v = m d / t

p = m v

v = d / t

p = Momentum

m = Mass

v = Velocity

d = Distance

t = Time

p = m v

m v = m d / t

Momentum is the quantity of an object with mass in motion. It is directly proportional to mass and velocity. Velocity is the rate of change of distance with respect to time.  

Therefore, the relationship between distance, time, mass, velocity, and momentum is p = m v = m d / t

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Answer:

45,000 J

General Formulas and Concepts:

Energy

Kinetic Energy Formula: \(\displaystyle KE = \frac{1}{2}mv^2\)

Explanation:

Step 1: Define

Identify variables

[Given] m = 900 kg

[Given] v = 10 m/s

Step 2: Solve for KE

Answer:

speed /wavelength = frequency

f = 3×10*8 /6.5×10*7

f = 4.62

The mass of Car B is -6000 kg.

To solve this problem, we can apply the principle of conservation of momentum, which states that the total momentum before the collision is equal to the total momentum after the collision.

Therefore, we can write the equation for the conservation of momentum as:

(mass of Car A * velocity of Car A) + (mass of Car B * velocity of Car B) = (mass of Car A + mass of Car B) * velocity after collision

Let's substitute the given values into the equation:

(2000 kg * 10 m/s) + (mass of Car B * 0 m/s) = (2000 kg + mass of Car B) * (-5 m/s)

Simplifying the equation:

20000 kg*m/s = -5 m/s * (2000 kg + mass of Car B)

Dividing both sides by -5 m/s:

-4000 kg = 2000 kg + mass of Car B

Subtracting 2000 kg from both sides:

mass of Car B = -4000 kg - 2000 kg

mass of Car B = -6000 kg

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The dependent variable in this experiment is: D. the time for the blocks to hit the ground.

An experiment can be defined as a scientific investigation which typically involves the process of manipulating an independent variable (the cause), so as to determine or measure the dependent variable (the effect).

In every experiment, there are two (2) main types of variables and these include the following:

In this scenario, we can infer and logically deduce that the dependent variable in this experiment is the time for the blocks to hit the ground because it signifies the effect of the independent variable (three blocks).

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Complete Question:

A student drops three blocks from the same height and measures the time it takes for the blocks to hit the ground. Each block has a different mass.

What is the dependent variable in the experiment?

A. the volume of the blocks

B. the drop height

C. the mass of the blocks

D. the time for the blocks to hit the ground

The x and y components of the plane's velocity is:

1. How do I determine the horizontal component (Vx) of the velocity?

We can obtain the horizontal component (Vx) of the velocity as illustrated below:

Vx = u × Cosθ

Vx = 40 × Cos 15

Vx = 38.6 m/s

Thus, the horizontal component (Vx) of velocity is 38.6 m/s

2. How do I determine the vertical component (Vy) of the velocity?

The vertical component (Vy) of the velocity can be obtained as

Vy = u × Sine θ

Vy = 40 × Sine 15

Vy = 10.4 m/s

Thus, the vertical component (Vy) of velocity is 10.4 m/s

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Answer:

Sparks often indicate the presence of a high voltage, or "potential field". The higher the voltage; the farther a spark can jump across a gap, and with enough energy supplied can lead to greater discharges such as a glow or an arc.

Explanation:

Answer:

a) y = 127.6 m, b) 11.9s,  c)  v = 103.6  m / s, θ’= 326.7º

Explanation:

This is a missile throwing exercise

let's start by breaking down the initial velocity

         sin 30 = \(\frac{v_{oy} }{v_o}\)

         cos 30 = v₀ₓ / v₀

         v_{oy} = v₀ go sin 30

         v₀ₓ = v₀ cos 30

         v_{oy} = 100 sin 30 = 50 m / s

         v₀ₓ = 100 cos 30 = 86.6 m / s

a) the maximum height is requested.

At this point the vertical velocity is zero (v_y = 0)

         v_y² = \(v_{oy}^2\) - 2 g y

         0 = v_{oy}^2 - 2g y

         y = \(\frac{v_{oy}^2 }{2g}\)

         y = 50² / (2  9.8)

         y = 127.6 m

b) Flight time

this is the time it takes to reach the ground, the reference system for this movement is taken on the ground this is a height of y = 0 m and the body is at an initial height of i = 100m

         y = y₀ + v₀ t - ½ g t²

       0 = 100 + 50 t - ½ 9.8 t²

we solve the quadratic equation

        4.9 t² - 50 t - 100 = 0

         t = \(\frac{50 \pm \sqrt{50^2 + 4 \ 4.9 \ 100} }{2 \ 4.9}\)

         t = \(\frac{50 \ \pm \ 66.8}{9.8}\)

         t₁ = 11.9 s

         t₂ = -8.4 s

flight time is 11.9s

c) The time 1 s before hitting the ground is

        t1 = 11.9 -1

        t1 = 10.9 s

let's find the vertical speed

       v_y =\(v_{oy}\) - g t

       v_y = 50 - 9.8 10.9

       v_y = -56.8 m / s

the negative sign indicates that the direction of the velocity is downward.

On the x-axis there is no acceleration therefore the speed is constant.

Let's use the Pythagorean theorem

        v = \(\sqrt{v_x^2+v_y^2}\)

        v = \(\sqrt { 86.6^2 + 56.8^2}\)

        v = 103.6  m / s

let's use trigonometry

        tan θ = \(\frac{v_y}{v_x}\)

        θ = tan⁻¹  \frac{v_y}{v_x}

        θ = tan⁻¹  (-56.8 / 86.60)

        θ = -33.3º

the negative sign indicates that it is measured clockwise from the x-axis

for a counterclockwise measurement

          θ’= 360 - θ

          θ' = 360 - 33.3

          θ’= 326.7º

A. The average speed you can use to pull the safe is 1.02 m/s

B. The time needed to pull the safe up is 17.65 s

First, we shall obtain the force. This is shown below:

F = mg

F = 60 × 9.8

F = 588 N

Finally, we shall obtain the average speed. Details below:

Power = force × average speed

600 = 588 × average speed

Divide both sides by 588

Average speed = 600 / 588

Average speed = 1.02 m/s

The time needed to pull the safe up can be obtained as follow:

Time = Total distance / average speed

Time = 18 / 1.02

Time = 17.65 s

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Complete question:

You know you can provide 600 W

of power to move large objects. You need to move a 60-kg

safe up to a storage loft, 18 m

above the floor.

Part A

With what average speed can you pull the safe straight up?

Part B

What is the time needed to pull the safe up?

Answer:

Two tuning forks with frequencies of 256 Hz and 512 Hz are struck. Which of the sounds will move faster through the air? Neither, the speed of sound is constant in air.

Answer:

The half-life is \( t_{1/2} = 1.005 h\)

Explanation:

Using the decay equation we have:

\(A=A_{0}e^{-\lambda t}\)

Where:

We know the activity decrease by a factor of two in a one hour period (t = 1 h), it means that \(A = \frac{A_{0}}{2}\)

\(\frac{A_{0}}{2}=A_{0}e^{-\lambda*1 h}\)

\(0.5=e^{-\lambda*1 h}\)

Taking the natural logarithm on each side we have:

\(ln(0.5)=-\lambda\)

\(\lambda=0.69 h^{-1}\)

Now, the relationship between the decay constant λ and the half-life t(1/2) is:

\(\lambda = \frac{ln(2)}{t_{1/2}}\)

\( t_{1/2} = \frac{ln(2)}{\lambda}\)

\( t_{1/2} = \frac{ln(2)}{0.69}\)

\( t_{1/2} = 1.005 h\)

I hope it helps you!

From the given options, let's select the correct Answer choice.

An acid can be said to be any substance containing hydrogen which can be able to donate hydrogen ions to another substance.

An acid does not feel slippery, rather it just feels wet. It is a base that is slippery.

An acid has a lower pH when compared to a base. pH less than 7 indicates acidity while pH greater than 7 indicates a base.

When an acid is added to water, the hydroxide ion concentration will reduce and the pH of yhe solution increases towards 7.

Therefore, an acid decreases the amount of ions in a water solution.

ANSWER:

a). Decreases the amount of ions in a water solution.

The vector with a magnitude of 5 and in the direction of the vector 4i - 3j + k is approximately (20/√26)i + (-15/√26)j + (5/√26)k.

The given vector can be normalized before being multiplied by the desired magnitude. This is how to locate the vector:

The vector that has been provided should be normalized by dividing each of its components by its magnitude. The Pythagorean theorem can be used to determine the magnitude of the vector 4i - 3j + k:

Magnitude = √(4² + (-3)² + 1²) = √(16 + 9 + 1) = √26

Normalize the vector by dividing each component by the magnitude:

Normalized vector = (4/√26)i + (-3/√26)j + (1/√26)k

Multiply the normalized vector by the desired magnitude:

To obtain a vector with a magnitude of 5, multiply each component of the normalized vector by 5:

Desired vector = 5 * ((4/√26)i + (-3/√26)j + (1/√26)k)

Simplifying the expression gives:

Desired vector ≈ (20/√26)i + (-15/√26)j + (5/√26)k

So, the vector with a magnitude of 5 and in the direction of the vector 4i - 3j + k is approximately (20/√26)i + (-15/√26)j + (5/√26)k.

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Answer:

HBr- polar covalent

Cl2 - nonpolar covalent

H2O - polar covalent

Explanation:

Covalent bonds are chemical bonds that holds atoms of elements in such a way that electrons are shared between the atoms. However, based on the electronegativity differences between elements, compounds can either be polar covalent or nonpolar covalent.

Polar covalent bonds are formed when electrons are unevenly shared between two atoms based on difference in their electronegativities i.e. the more electronegative atom pulls more of the electrons. For example, in the case of HBr and H2O, Bromine and Oxygen atoms are more electronegative, hence, they pull more electrons making the electron sharing unequal, hence, a POLAR COVALENT BOND forms.

Non polar covalent bonds, contrarily, occurs when electrons are shared equally or evenly. This is so because the atoms of the elements involved have the same electronegativity. For example, Cl2 contains two atoms of Chlorine (Cl), which has the same electronegativity, hence, electrons between the two atoms are shared equally to form a NONPOLAR COVALENT BOND

HBr is polar covalent, Cl₂ - nonpolar covalent and H₂O is polar covalent in nature.

When atoms with differing electronegativities share electrons in a covalent link, the result is a polar covalent bond.

Consider the molecule of hydrogen chloride (HCl). In order to generate an inert gas electron configuration, each atom in HCl requires one extra electron.

Covalent bonds are chemical bonds that keep atoms of different elements together while sharing electrons.

Compounds can be polar covalent or nonpolar covalent depending on the electronegativity variations between components.

When electrons are unevenly divided between two atoms due to differences in their electronegativities, polar covalent connections are created.

The more electronegative atom draws more electrons. In the case of HBr and H2O, for example, the Bromine and Oxygen atoms are more electronegative,

Therefore they draw more electrons, causing the electron sharing to be uneven, resulting in the formation of a polar covalent bond.

Hence HBr is polar covalent, Cl₂ - nonpolar covalent and H₂O is polar covalent in nature.

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The Falcon 9 rocket is so important in today's space exploration world because It's a reusable rocket and has saved money by being reused over 60 times already.

option D.

The Falcon 9 rocket, is developed by SpaceX, and it holds  a significant importance in today's space exploration world due to several key features and achievements, and some of the importance include the following;

From the given options, we can conclude that the Falcon 9 rocket is so important in today's space exploration world because It's a reusable rocket and has saved money by being reused over 60 times already.

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projectile's vertical speed v yv y v, start , y,  drops prior to reaching its maximum height since its acceleration is in the opposite direction. Since the object's height is rising, the initial direction of the velocity is upward

.

At the projectile's highest point, vertical velocity zeroes out. After reaching the highest point, the vertical speed increases due of the same-direction acceleration. As the object's height lowers, the vertical velocity has a downward direction.

In projectile The beginning vertical velocity determines the maximum height. Increasing the launch angle raises the maximum height because steeper launch angles have a larger vertical velocity component.

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Option A) 3.9 km is the correct answer. the magnitude of Rhea's displacement vector is approximately 3.92 km.

In order to find out the magnitude of Rhea's displacement vector, we have to add up all of the displacement vectors.

Then we can use the Pythagorean theorem to calculate the magnitude of the resultant vector.

Since Rhea is first driving north for 2.4 km and then west for 3.1 km, we can represent her displacement vectors as follows: Δx = 0 km and Δy = 2.4 km for the first vector, and Δx = -3.1 km and Δy = 0 km for the second vector.

We can then add these vectors together by adding their components: Δx = 0 km + (-3.1 km) = -3.1 km and Δy = 2.4 km + 0 km = 2.4 km.

This gives us a resultant vector of -3.1 km east and 2.4 km north.

Using the Pythagorean theorem, we can find the magnitude of this vector: \(\sqrt{(\(-3.1 km)^{2} + (2.4 km)^{2} ) } = \sqrt{(9.61 + 5.76) km^{2} } = \sqrt{15.37 km^{2} } \approx 3.92 km.\)

Therefore, the magnitude of Rhea's displacement vector is approximately 3.92 km.

Therefore, option A) 3.9 km is the correct answer.

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Answer:

10800 kg m/s

Explanation:

Since the dumpster was initially at rest, its momentum before collision equal to zero. So that the total momentum of the car and dumpster before collision is 10800 kg m/s.

The principle of conservation of linear momentum states that: in a system of colliding bodies, total momentum is conserved. Therefore, the total momentum of the car and dumpster after collision is 10800 kg m/s.

Answer:

A. When two surfaces are moving relative to each other.

Explanation:

It is also know as dynamic friction

The probability mass function is obtained as:

\(p(x=x)=12 c_x \quad(0.4)^x(1-0.4)^{1 x-x} ; x=0,1,2 \ldots .12\)

Outcome is,

\(n=12 \\ p=0.4\)

Let X be discrete random variable which takes value \($i=1,2 \ldots$\).

Now the probability of mass function at point is is given by:

\(p(x=p)=p\left(x_i\right)=F\left(x_i\right)-F\left(x_{(i-1)}\right)\)

By using Bernoulli's random variable:

\(P(x=x)=p^x(1-p)^{1-x} x=0,1\)

where as \($x=0 \Rightarrow$\) corresponds to failure

\($x=1 \Rightarrow$\) correspond to Success

p is probability function of Success.

Therefore the total number of Success in ' n ' independent Bernoulli trials is Sum of ' n ' bernoulis random variable which gives binomial distribution.

By using multiplication rule the probability of observing ' x 'Successes in ' n ' independent bernoulli trials it can be written as:

\(\underbrace{p \times p \times \ldots \times p}_{x \text { times }} \times(\underbrace{() 1-p) \times(1-p) \times \ldots \times(1-p)}_{n-x \text { times }}\)

The probability mass function :

\(p(x=x)=12 c_x \quad(0.4)^x(1-0.4)^{1 x-x} ; x=0,1,2 \ldots .12\)

where as

\(n=12 \\ p=0.4\)

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Note:- The question is as follow,

Consider the probability space \($(S, M, P)$\) that models the observed proportion of successes in n independent Bernoulli trials with probability of success equal to p. For example, given n=12 and p=0.4, the outcome \(\frac{5}{12}=.41 \overline{6} \:in $(S, M, P)$\) should have the same probability as the outcome of 5 successes in 12 independent Bernoulli trials with probability of success equal to 0.4. Give a formula for the density function f(s) for this probability space in terms of the density \($f_{n, p}$\) of the binomial distribution with size n and probability p. ( points)

The statement "B. Gravity exists only on Earth" and the statement "E. Gravity doesn't exist between Earth and the sun"  is not true about gravity.

Gravity is a fundamental force of nature that exists in the whole universe, not just on Earth. It is a force that acts between any two objects that have mass. This means that statement "C. Gravity is a force that pulls two objects together" and "D. Gravity exists between two objects that have mass" are both true. Gravity plays a significant role in the functioning of our solar system. The sun's gravitational force acts on the planets, including Earth, keeping them in their orbits. Similarly, Earth's gravitational force attracts objects towards its center, giving weight to objects on its surface. Gravity is the force that holds Earth in orbit around the sun and is responsible for the planets' motion in the solar system. Gravity is a universal force that exists throughout the universe, acts between objects with mass, and plays a crucial role in celestial bodies' movements, including the interaction between Earth and the sun.

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Precipitation amount, storm frequency, and severity, storm duration, kind of precipitation, wind during storm, and wind during evaporation are the main precipitation and storm elements that influence interruption loss (Kenneth, 1996).

All procedures that stop rainfall from instantly reaching the soil are referred to as interceptions. The two main ways that vegetation intercepts water are by catching it on leaf surfaces throughout the canopy and by depositing litter on the ground.

Precipitation that is intercepted by leaves, plant branches, and the forest floor prevents it from reaching the soil and instead stays on the surface.

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