Please help I need finish by 10:57

Answer:

0.74 m/s

Explanation:

From the question,

We apply the law of conservation of momentum,

Total momentum before collision = Total momentum after collision.

Since the skateboard, the person and the brick where stationary, therefore, the total momentum before collision is 0

0 = Total momentum after collision

(m+M)V + m'v = 0

Where m = mass of the  skateboard, M = mass of the person, m' = mass of the brick, V = recoil velocity of the person and the skateboard, v =  velocity of the brick

make V the subject of the equation above

V = -m'v/(m+M)................... Equation 1

Given: m = 4.10 kg, M = 68.0 kg, m' = 2.50 kg, v = 21.0 m/s.

Substitute these values into equation 1

V = -(2.5×21)/(68+2.5)

V = 52.50/70.5

V = 0.74 m/s

The volume of snow on the lawn, in cubic m, is 44.63 or 44.63 m³ if the lawn outside your neighbor's house has an approximate area of 175 m².

It is defined as a three-dimensional space enclosed by an object or thing.

It is given that:

The lawn outside your neighbor's house has an approximate area of 175 m². One night it snows so that the snow on the lawn has a uniform depth of 25.5 cm.

As we know, unit conversion can be defined as the conversion from one quantity unit to another quantity unit followed by the process of division, and multiplication by a conversion factor.

25.5 cm =  0.255 m

Volume = area×depth

Volume = 175×0.255

Volume = 44.63 cubic meters

Thus, the volume of snow on the lawn, in cubic m is 44.63 or 44.63 m³ if the lawn outside your neighbor's house has an approximate area of 175 m².

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Answer:

Explanation:

velocity of sound in air at 20⁰C is 343 m /s

velocity of sound in water at 20⁰C is 1481 m /s

The wavelength of the sound is 2.86 m in the air so its frequency

= 343 / 2.86 = 119.93 .

This frequency of  119.93 will remain unchanged in water .

wavelength in water = velocity in water / frequency

= 1481 / 119.93

= 12. 35 m .

Answer:

the correct answer to increase the thickness of the windows

Explanation:

Thermal transfer by conduction is

           P = k A   [tex]( \frac{ T_h - T_c}{L} )[/tex]

where P is the heat transfer rate, A is the area and L is the thickness

In the given case we have that the window is made up of two materials, two layers of transparent glass and a layer of air between them, let us use the index 1 for the glass and the index 2 for the air, the equation remains

           P =[tex]k_1 A_1 \frac{ \Delta T }{2 \ e_1} + k_2 A_2 \frac{ \Delta T}{e_2}[/tex]

where the number two (2) is due to the two layers of glass

the thermal conductivity of the glass is k₁ = 0.75 W/m K for a glass of

e₁ = 4 mm, this is more used for windows

the thermal conductivity of the air is k₂ = 0.024 W / m K for a temperature of T = 0ºC

In a window the area and the temperature difference are constant for each part for a given configuration

           P = [tex]( \frac{k_1}{2 \ e_1} + \frac{k_2 }{ e_2} )[/tex]   A ΔT

To decrease the speed of thermal transfer we can decrease the area, but this also reduces the lighting in the room, which brings other costs.

We can also increase the thickness of the materials, as we see the thermal conductivity of the air is very less than that of glass

                k₂  « k₁

increasing the thickness of the air layer would have the greatest effect is the decrease in heat transfer in window light

consequently the correct answer to increase the thickness of the windows

Answer:

those who are attracted to magnets. ex: iron, cobalt and nickel

Answer:

W = 65.04 μW

Explanation:

For this exercise we will use the definition of sound intensity which is the power per unit area

           I = W / A

In this case, they indicate that for the intensity of the first student is I1 = 0.58 W / m², and the intensity of the second student is

            I₂ = 1.18 I₁

            I₂ = 1.18 0.58

            I₂ = 0.6844 W / m²

Ask the power

              W = I A

the diameter of the size is 1.1 cm and the radius is r = 0.55 cm = 0.55 10⁻² m, the approximate eardrum area as a circle

             A = π r²

we substitute

             W = I π r²

let's calculate

             W = 0.6844 π (0.55 10⁻²)²

             W = 6.504 10⁻⁵ W

they ask us to reduce to microwatts

              W = 6.504 10⁻⁵ W (106 μW / 1W)

              W = 65.04 μW

the power is constant, what changes is the intensity that depends on the sensor area, therefore the two students review the same power

Acoustic power, in microwatt W is 65.04 μW

We know that;

I = W / a

In case 1;

I1 = 0.58 W / m²

So, I₂ = 1.18 I₁

I₂ = 1.18 × 0.58

I₂ = 0.6844 W / m²

Diameter of the size = 1.1 cm

So,

Radius r = 1.1/2 = 0.55 cm

Area A = πr²W = Iπr²

W = 0.6844(3.4)(0.55)²

W = 6.504 × 10⁻⁵ W

Acoustic power, in microwatt W = 65.04 μW

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Answer:

4.80 m

Explanation:

We are given the mass of the high jumper, its initial velocity, and the acceleration of gravity. We are trying to find the vertical displacement of the high jumper.

Let's set the upwards direction to be positive and the downwards direction to be negative.

List out the relevant known variables.

We still need one more variable in order to use the constant acceleration equations. Since we are trying to find the max height of the jumper, we can use the fact that at the top of its trajectory, its final velocity will be 0 m/s.

    4. v = 0 m/s

Using these four variables, let's find the constant acceleration equation that contains these variables:

Substitute the known values into the equation and solve for Δx.

The high jumper can jump to a max height of 4.80 m.

Answer:

4)

Explanation:

Efficiency is calculated by dividing the energy out by energy in, not multiplying

No machines are 100% Efficient

No machines are frictionless

4) is true

Answer:

   F = 1494.52 N,   θ = 44º

Explanation:

For the sum of vectors by the parallelogram method, see attached, the vectors are drawn, the parallelogram is completed and a vector is drawn from the origin of the two vectors to the end point of the rectangle, this is the resulting vector.

The attachment shows this roughly.

For the Cartesian coordinate method, each vector is decomposed into its components, they are added algebraically and then the resulting vector is composed in the form of a module and angles

we use trigonometry to decompose the vectors.

The coordinate system can be seen in the attachment

           sin θ = y / R

           cos θ = x / R

            y = R sin θ

            x = R cos θ

Vector 1

module F₁ and angle β₁ = 50

            sin 50 = [tex]\frac{F_{1y} }{F_1}[/tex]

            cos 50 = [tex]\frac{F_{1x} }{F_1}[/tex]

            [tex]F_{1y}[/tex] = F₁ sin 50

            F₁ₓ = F₁ cos 50

            F_{1y} = 600 sin 50 = 459.63 N

            F₁ₓ = 600 cos 50 = 385.67 N

Vector 2

modulus F₂ = 900N, angle β₂ = 40

            F_{2y} = 900 sin 40 = 578.51 N

            F₂ₓ = 900 cos 40 = 689.44 N

we find the resultant of each component

           F_{y} =F_{1y} + F_{2y}

           F_{y}  = 459.63 + 578.51

           F_{y}  = 1038.14 N

            Fₓ = F₁ₓ + F₂ₓ

            Fₓ = 385.67 + 689.44

             Fₓ = 1075.11 N

We use the Pythagorean theorem to find the modulus of the resultant

            F = Fₓ² + [tex]F_{y}^2[/tex]

            F = √(1075.11² + 1038.14²)

            F = 1494.52 N

we use trigonometry for the angle

            tan θ = F_y / Fₓ

            θ = tan⁻¹ (F_y / Fₓ)

            θ = tan⁻¹ (1038.14 / 1075.11)

            θ = 44º

Answer:

1)   [tex]kinectic energy=7.26*10^-^2^0J[/tex]

2)  [tex]V= 2.0m/s[/tex]

3)  [tex]T=3.5*10^3K[/tex]

4)  The Molecules do not burn because of the presences of hydrogen bond in place

Explanation:

From the question we are told that

latent heat of vaporization for water at room temperature is 2430 J/g.

1)Generally in determining the molar mass of water evaporated we have that

-One mole (6.02 x 10. 23 molecules)

-Molar mass of water is 18.02 g/mol

Mathematically the mass of water is give as

  [tex]M=\frac{18.02}{6.02*10^-^2^6}[/tex]

  [tex]M=3*10^-^2^3g[/tex]

Therefore

  [tex]kinectic energy=2430J/g*3*10^-^2^3g[/tex]

 [tex]kinectic energy=7.26*10^-^2^0J[/tex]

b)Generally the evaporation speed V is given as[tex]V= \sqrt{\frac{K.E*2}{m} }[/tex]

Mathematically derived from the equation

[tex]\frac{1}{2} mv^2 =K.E[/tex]

To Give

[tex]V= \sqrt{\frac{K.E*2}{m} }[/tex]

[tex]V= \sqrt{\frac{7.26*10^-^2^0J*2}{3*10^-^2^3g} }[/tex]

[tex]V= 2.0m/s[/tex]

c)Generally the equation for velocity   [tex]Vrms=\sqrt{\frac{3RT}{M} }[/tex]

Therefore

Effective temperature T is given by

      [tex]T=\frac{\sqrt{v}*m}{R}[/tex]

where

     [tex]T=\frac{\sqrt{2.0m/s}*6.02*10^-^2^6}{0.082057 L atm mol-1K-1}[/tex]

     [tex]T=3.5*10^3K[/tex]

4) The Molecules do not burn because of the presences of hydrogen bond in place

Answer: the mass is 1.60 kg and the acceleration on the rocket is...

58.4 m/s with a Power of Two

Explanation:

A model rocket lifting off from the launch pad is a good example of this principle. Just prior to engine ignition, the velocity of the rocket is zero and the rocket is at rest. If the rocket is sitting on its fins, the weight of the rocket is balanced by the re-action of the earth to the weight as described by Newton's third law of motion. There is no net force on the object, and the rocket would remain at rest indefinitely. When the engine is ignited, the thrust of the engine creates an additional force opposed to the weight. As long as the thrust is less than the weight, the combination of the thrust and the re-action force through the fins balance the weight and there is no net external force and the rocket stays on the pad. When the thrust is equal to the weight, there is no longer any re-action force through the fins, but the net force on the rocket is still zero. When the thrust is greater than the weight, there is a net external force equal to the thrust minus the weight, and the rocket begins to rise. The velocity of the rocket increases from zero to some positive value under the acceleration produced by the net external force. But as the rocket velocity increases, it encounters air resistance, or drag, which opposes the motion and increases as the square of the velocity. The thrust of the rocket must be greater than the weight plus the drag for the rocket to continue accelerating. If the thrust becomes equal to the weight plus the drag, the rocket will continue to climb at a fixed velocity, but it will not accelerate.

Answer:

54m

Explanation:

Given parameters:

Initial velocity  = 0m/s

Time taken  = 6s

Final velocity  = 18m/s east

Unknow:

How far did the object travel  = ?

Solution:

To solve this problem, we use one of the kinematics equation:

 We first find the acceleration which is the change in velocity

So;

        S  = [tex](\frac{v - u}{2} ) t[/tex]    

    S is the distance  

    v is the final velocity

    u is the initial velocity

    t is the time taken

  Therefore;

       S = [tex]\frac{18 - 0}{2}[/tex]  x 6  = 54m

the dig would -5 from where he first started.

Slope is rise over run, meaning the ratio of the change in height to the change in horizontal distance. So a slope of 15.80 corresponds to an angle of ascension θ of

tan(θ) = 15.80   →   θ ≈ 86.38°

The order of the blocks (i.e. whether the large one is pulling the smaller one up or vice versa) does not matter, since friction is not a concern. So if we take the connected blocks as a single mass, by Newton's law we have a net force acting parallel to the incline of

∑ F = P - (M + m) g sin(θ) = (M + m) a

(see the attached free body diagram)

where

P = magnitude of the push

g = 9.80 m/s²

a = 2.53 m/s²

and M and m are the given masses.

Then the system requires a push of

P = (M + m) (a + g sin(θ))

P = (14.2 kg + 4.73 kg) (2.53 m/s² + (9.80 m/s²) sin(86.38°))

P ≈ 233 N

If you have to find the tension in the rope, consider the free body diagram for one of the blocks. By Newton's second law, the net parallel force acting on, say, the larger block (if it's being pulled by the rope) is

∑ F = T - M g sin(θ) = M a

where

T = tension in the rope

Then

T = M (a + g sin(θ))

T = (14.2 kg) (2.53 m/s² + (9.80 m/s²) sin(86.38°))

T ≈ 175 N

Answer:

[a]. South direction

(b). 1.354 × 10^14 m/s^2

Explanation:

In order to to be able to solve this question effectively, one must be familiar with physics concepts such as kinetic energy[1/2 ×mass × velocity,v²], magnetic force[ magnetic force = charge × velocity × magnetic field × sin Ф] and Newton's law of motion especially the second law of Newton[ Force = mass × acceleration].  

(a). The direction are the electrons deflected by this field component = q( v × B) = - (  i × -k) = -( - ( i × k) = - (- (- j) = -j. The -j is in the south direction.

Note that  i × k is being replaced by -j.

(b). In order to determine the magnitude of the acceleration of an electron in part (a), the first thing to do is to calculate the velocity from the equation for kinetic energy.

Thus, velocity = √ [(2 × 2.7 × 10⁻¹⁵) ÷ 9.1 × 10⁻³¹] = 7.7 × 10^7 m/s.

The next thing is to determine the net force.

Therefore, the net force = 1.6 × 10^-19 × 7.7 × 10^7 m/s × 1 × 10^-15 sin 90°.

= 1.232 × 10^ -16N.

Hence, Net Force = mass × acceleration.

1.232 × 10^ -16N = 9.1× 10^-31 × acceleration.

The acceleration = 1.232 × 10^ -16N/ 9.1× 10^-31 = 1.354 × 10^14 m/s^2.

Answer:

5.6875 × 10^(10) electrons

Explanation:

To some this we will use the formula;

q = ne

Where;

q is charge

n is number of electrons

e is electron charge = 1.6 × 10^(-19) C

We are given q = -9.10 nc

1 nc = 10^(-9) C

Thus;

q = -9.1 × 10^(-9) C

Since q is negative, then e = -1.6 × 10^(-19) C

Thus;

-9.1 × 10^(-9) = n(-1.6 × 10^(-19))

n = -(9.1 × 10^(-9))/(-1.6 × 10^(-19))

n = 56875000000 electrons = 5.6875 × 10^(10) electrons

Answer:

25.5 pounds per square inch are equivalent to 1.735 atmospheres.

Explanation:

An atmosphere equals 14.695 pounds per square inch. We find the equivalent of given pressure in atmospheres by means of simple rule of three:

[tex]x = 25.5\,\frac{lb}{in^{2}} \times \frac{1\,atm}{14.695\,\frac{lb}{in^{2}} }[/tex]

[tex]x = 1.735\,atm[/tex]

25.5 pounds per square inch are equivalent to 1.735 atmospheres.

Answer:

This is Introvert ting

Explanation:

u know when people are shy

i think they r known as Introvert

i hope this helps

Answer:

0.71 m/s

Explanation:

We find the time it takes the stone to hit the water.

Using y = ut - 1/2gt² where y = height of bridge, u = initial speed of stone = 0 m/s, g = acceleration due to gravity = -9.8 m/s² (negative since it is directed downwards)and t = time it takes the stone to hit the water surface.

So, substituting the values of the variables into the equation, we have

y = ut - 1/2gt²

82.2 m = (0m/s)t - 1/2( -9.8 m/s²)t²

82.2 m = 0 + (4.9 m/s²)t²

82.2 m =  (4.9 m/s²)t²

t²  = 82.2 m/4.9 m/s²

t² = 16.78 s²

t = √16.78 s²

t = 4.1 s

This is also the time it takes the raft to move from 5.04 m before the bridge to 2.13 m before the bridge. So, the distance moved by the raft in time t = 4.1 s is 5.04 m - 2.13 m = 2.91 m.

Since speed = distance/time, the raft's speed v = 2.91 m/4.1 s = 0.71 m/s

Answer: 7

Explanation: 7 is the superior number

Answer:

1,269 N

Explanation:

I guessed and got the question right on CK-12's work practice.

Answer:

6.309573e+16 joule is released by an earthquake of magnitude 8

Answer:

An earthquake with a magnitude of 8 on the Richter scale releases 6.309573e+16 J of energy.

Explanation:

An earthquake with a magnitude of 8 on the Richter scale releases 6.309573e+16 J of energy.

Answer:

they are identical.

Explanation:

use coulomb law. the size of that line is just to confuse students because some sick teacher gets off on making you miss points. coulombs law says the magnitude of electric field is proportional to the size of the charge. here they are all +/-1 they are the same.

The true statement is "The electric force between A and B is greater than the electric force between C and D." The correct answer is B.

Electric force, also known as Coulomb force, is the attraction or repulsion between electrically charged particles. It is a fundamental force of nature that arises from the interaction of charged particles with each other. Electric force is described mathematically by Coulomb's law, which states that the magnitude of the force between two point charges is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. The direction of the force depends on the sign of the charges, with like charges repelling each other and opposite charges attracting each other.

Here in the Question,

The electric force between two charged objects depends on the magnitude of the charges and the distance between them. In this case, object A has a positive charge and object B has a negative charge, so there is an attractive force between them. Object C also has a positive charge, but it is separated by a larger distance from the negative charge at point D, so the electric force between C and D is weaker than the force between A and B.

Option A is not true because the distance between A and B is smaller than the distance between C and D, so the forces cannot be identical in magnitude.

Option C is not true because, as explained above, the force between A and B is greater than the force between C and D.

Option D is not true because the forces between A and B and between C and D are not opposite in direction, so they cannot cancel each other out.

Therefore, The correct answer is B. The electric force between A and B is greater than the electric force between C and D.

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Answer:

A = 4.49

α = 57.72°

Explanation:

Knowing the magnitude of x & y of a vector we can determine the total magnitude of a vector.

[tex]A=\sqrt{A_{x}^{2} +A_{y}^{2} } \\A=\sqrt{(2.4)^{2} +(3.8)^{2} }\\A=4.49[/tex]

The angle tangent can be used to determine the angle.

[tex]tan(\alpha )=\frac{3.8}{2.4}\\tan(\alpha ) =1.5833\\\alpha =tan^{-1}(1.5833) \\\alpha = 57.72 (deg)[/tex]

Answer:

V = 23.6062 cm³

General Formulas and Concepts:

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Gas Laws

Explanation:

Step 1: Define

Mass m = 455.6 g

Density D = 19.3 g/cm³

Step 2: Solve for V

Answer:

is the fastest moving type of radiationhe

Answer:

2.40 Km/hr.

Explanation:

From the question given above, the following data were obtained:

Mass of truck (m₁) = 3500 kg

Velocity of truck (u₁) = 7 Km/hr

Mass of car (m₂) = 1200 kg

Velocity of car (u₂) = 11 km/hr

Post collision velocity (v) =?

The post collision velocity of the truck and car can be obtained as illustrated below:

m₁u₁ – m₂u₂ = v(m₁ + m₂)

(3500 × 7) – (1200 × 11) = v(3500 + 1200)

24500 – 13200 = v × 4700

11300 = v × 4700

Divide both side by 4700

v = 11300 / 4700

v = 2.40 Km/hr.

Therefore, the post collision velocity of the truck and car is 2.40 Km/hr.

Answer:

Explanation:

Moment of inertia of toy top = 3 x 10⁻²   kgm²

Torque created = F x r

= .30 x 2.5 x 10⁻² N m

Torque = moment of inertia x angular acceleration

angular acceleration = .3 x 2.5 x 10⁻² / 3 x 10⁻²

α = .25 radian /s²

Angular displacement in 5 revolution θ = 5 x 2π = 10π radian

θ = ω₀t + 1/2 α t²

initial angular velocity ω₀ = 0

10π = 1/2 α t² = .5 x .25 t²

t² = 251.2

t = 15.85 s

Answer:

₮₣ ₮₣ ₮₣ ₮₣ ₮₣ ₮₣ ₣5₣ đ₮ɽ ₮₣ ₮ɽ

Explanation:

[tex]miles \: to \: km \\ = 1.2 \: miles \times \frac{1 \: km}{1.6093 \: miles} \\ = 0.7457 \\ \\ km \: to \: feet \\ = 1.8 \: km \times \frac{3280 \: ft}{1 \: km} \\ = 5904 \: ft[/tex]