large dorm, half the rooms are randomly wired for high-speed internet connections (the treatment group), and final course grades are collected for all residents. Which of the following pose threats to internal validity, and why? a. Midway through the year all the male athletes move into a fraternity and drop out of the study (their final grades are not observed). b. Engineering students assigned to the control group put together a local area network so that they can share a private wireless internet connection that they pay fo

The weight of a ball of the same material with a 3-inch radius is 12.15 pounds.

All things close to Earth are constantly subject to the force known as weight. All items are pulled downward toward the Earth's center by the gravity of the planet.

As a result, kilograms times meters per second squared, which is equivalent to a newton, can be used to quantify weight in the SI (N).

Weight can be expressed using the formula W = m*g, where weight can be expressed as kg * m/s2, which is equivalent to N, since weight is the force that gravity extends on a mass.

Let w equal the ball's weight in pounds.

r is the spherical ball's radius in inches.

The constant, C, converts the connection into a formula and ensures that the units are calculated correctly.

So, w = C r 3.

First determine C using the 2 "example: C= w/r3 = 3.60/(2)3 = 3.60/8 = 0.45

Now that you know C, you can determine the larger 3's weight "ball:

w = 0.45 r3 = 0.45

3  = 0.45 (27) = 12.15 pounds

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Answer:

Explanation:

a

The motion of the box changes as it will move slower because as the mass increases, the force of friction between the surface also increases. Thus, the correct option is A.

Force of friction is a type of contact force. Frictional force is the force which resists the motion when the surface of one object comes in contact with the surface of another object. Example of frictional force is the force of friction between two stones which are rubbed with each other. The SI unit of frictional force is Newton (N).

Frictional force can be calculated by the formula:

f = μN

where, f = frictional force,

μ = coefficient of friction,

N = Normal force

The mass of the objects (normal force - mg) which are in motion is directly proportional to the magnitude of the frictional force. As more books are added to the box while the force of push remains same the motion of the box will change and it will move slower because as mass increases, the force of friction between the surface also increases.

Therefore, the correct option is A.

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Answer:

The maximum coefficient of static friction required to pull the box will be 0.4.

Explanation:

We have given a box of mass 2 kg and Force of 50 N. (g=10m/s)

As we know,

Coefficient of static friction: μ = F/N (I)(F=ma, a= g)

Putting value in equation (I), we get

μ= mg/

μ=2×10/50

μ=0.4

Answer:

5×10-5 farads

Explanation:

Indications:

Q = charge

I = Current

t = Time

C = Capacitance

V = Voltage

Now, we know, Q = IT = 2×10^-5 ×30 = 6×10^-4 C

again, we know, Q = VC

⇒ C = Q/V = 6×10^-4/12 = 5×10^-5 Farads

The length of the pendulum is 0.910m if acceleration due to gravity is 9.8 m/[tex]s^{2}[/tex] and it takes 24 s to go 14 cycles.

First we will calculate Time period of pendulum

T = no of oscillations/ time

= 14/24

= 0.5833

We can find length of pendulum using formula

L=g(T/2π)^2

= 9.8(0.583/2×3.14

=9.8(0.583/6.28)

= 0.910 m

A simple pendulum is an arrangement of oscillating bob that has periodic motion. The simple pendulum has a small bob of mass ‘m’ suspended by a thin string fixed to a platform and length of string is L.

The time taken to complete one oscillation is defined as the time period of the pendulum. For simple pendulum of length L , time period is T = 2π √R/2g.

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The paddle will experience a force from the water equal to the product of the water pressure and the paddle's surface area.

what is pressure ?

Pressure (symbol: p or P) is the force applied perpendicular to the surface of an object per unit area across which that force is distribute  Gauge pressure (sometimes called gauge pressure)[a] is the pressure relative to the ambient pressure.

Various units are used to express pressure. Some of these are derived from dividing a unit of force by a unit of area; for example, the SI unit of pressure, the pascal (Pa), is one newton per square metre (N/m2); similarly, the pound-force per square inch (psi) is the conventional unit of pressure in the imperial and US customary systems. Pressure can also be stated in terms of normal atmospheric pressure; this pressure equals the atmosphere (atm).

The paddle will experience a force from the water equal to the product of the water pressure and the paddle's surface area. Any more power will only go to raise the speed of the paddle. Because of this, more water may be forced into a smaller space.

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Answer: The answer is ture

Explanation: Newtons third law which says

The vehicle's last speed if −3.00 MJ of work was finished by the brakes will be 398.45 km each hour.

What is the conservation of energy?

According to the principle of conservation of mass, energy cannot be gained or lost; it can only be converted from one form of energy to another. This indicates that only if energy is introduced from outside, a unit always uses the same quantity of energy.

In 1979, Dr. Hans Liebold of Germany drove a race vehicle 12.6 km with a typical speed of 404 km/h. Assume Liebold applied the brakes to decrease his speed. Expect the consolidated mass of the vehicle and driver to be 1.00 and 103 kg.

The final speed is given as,

1/2 x m [(v₂)² - (v₁)²] = 3 x 10⁶

1/2 x (1 + 103) x [(v₂)² - (404 x 18/5)²] = 3 x 10⁶

(v₂)² = 2057687.06

v₂ = 1,434.43 m/s

v₂ = 398.45 km per hour

The vehicle's last speed if −3.00 MJ of work was finished by the brakes will be 398.45 km each hour.

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Answer:

It will 50 m time Taken to complete one round time taken to complete complete one one round, it will nine second. So distance covered in, covered in in one ground equal two prior to that is equal to pi In 250, 1200 five. Now everybody spirit average period equal fear equal distance upon

when the temperature is kept constant, to increase the volume of the gas, you will decrease the pressure (Option D)

The volume of a gas at constant temperature is explained by the Boyle's law equation which is states as follow:

The volume of a fixed mass of gas is inversely proportional to the pressure at conctant temperature. Mathematically, it is expressed as follow:

P ∝ = 1/V

P = K / V

P₁V₁ = P₂V₂

Where

From the above formula, we can see that volume and pressure exist in inverse proportionality. This means that when the volume increases, the pressure will decrease and also, when the volume decreases, the presure will increase.

With the above information, we can conclude that the correct answer to the question is: You would decrease the pressure (Option D)

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Speed is the rate of motion, and velocity contains a direction of the rate of motion, so the blank space is filled by "direction".

When anything is moving, its velocity tells us how quickly that something's location is changing from a certain vantage point and as measured by a particular unit of time.

If a point moves along a path and covers a certain distance in a predetermined amount of time, its average speed over that period of time is equal to the distance covered divided by the travel time. A train traveling 100 kilometers in two hours, for instance, is doing it at an average speed of 50 km/h.

Speed is only given the magnitude of the rate of motion, while velocity is given the direction of the rate of motion,

Therefore, Speed is the rate of motion, and velocity contains a direction of the rate of motion.

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20.273° is the angle of refraction of the light as it enters the water from the glass.

Snell's law states that the angle of refraction, θr, is proportional to the angle of incidence, θi and the ratio of the refractive indices of the two media that comprise the interface. The angle θr=θi and no refraction occur when the mediums have equal refractive indices.

Given that,

Saltwater has an index of refraction = 1.33

The glass has an index of refraction (n₁) = 1.53

Air has an index of refraction (n₂) = 1.000293.

According to Snell's law:

n₂/n₁ = sin θ₁ / sin θ₂

or, 1.000293 / 1.53 = sin θ₁ / sin (32°)

or, 0.6537 = sin θ₁ / 0.52992

or, 0.3465 = sin θ₁

or, θ₁ = sin⁻¹ (0.3465)

or, θ₁ = 20.273°

So, 20.273° is the angle of refraction of the light as it enters the water from the glass.

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As the object moves from point A to B, the kinetic energy of the object decreases and the mechanical energy of the object increases.

In this problem, the law of energy conservation is applied. It is given that the work done by conservative force is -70J and the work done by non-conservative force is 50J.

The resulting forces between these two forces is -70J + 50J = -20 J.

The conservative force is linked with the movement caused by the sum of two energies, therefore there is a decrease in kinetic energy. The increase in mechanical energy is due to the positive non-conservative force.

Thus, the correct answer is kinetic energy of the object decreases and the mechanical energy increases.

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For x be the number of rolls of a die needed for all 6 numbers to turn up then the expected value is 5 and the variance of x is 2.0833 .

But to be absolutely certain, we may apply an even more straightforward procedure to get the solution,

expected value = (1 -p)/p

Where p is the likelihood of success and (1-p) is the expected failure value for the number of rolls of a die needed for all 6 numbers to turn up.

Thus , the 6 number to turn up = p = 1/6

The 6 number to not turn up =(1 - p) = 5/6

Putting the value in above equation we get,

expected value = (1 - 1/6)/1/6 = (5/6)/(1/6)

expected value = 5

Thus, all outcomes on the die between 1 and 6 have an equal likelihood,  the bounds are a = 1, b = 6 ,now calculating the variance of x i.e. V(x)

V(X) = ( b - a)²/12

V(X) = ( 6 - 1)²/12

V(X) = 2.0833

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A balanced force is referred to as when all the applied forces create an equilibrium which is therefore denoted as option A.

This is referred to as an influence that can change the motion of an object and the formulas is F= ma where m is the mass and a is acceleration of the body involved with its unit being Newton.

Equilibrium on the other hand  is referred to as as a state in which all the individual forces and torques exerted upon an object are balanced and there is no movement of the body in any type of direction in this type of scenario.

Balanced force is referred to as a situation in which all the applied forces which creates an equilibrium as denoted above which is therefore the reason why option A was chosen as the correct choice.

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Answer:

bro what is this

The primary cause of the decision-making and construction process delays is a lack of knowledge. Never criticize a teammate in front of other teammates or the manager when giving them constructive criticism.

A great deal is that more information is required to portray the current structure, its background, and its make-up. They can go get another dam consulting engineer if it is too much trouble for them or if they don't like it.

However, there are a few things that are quite challenging to adhere to:

The absence of information in the query is what makes all of these challenges difficult. Thus, it is clear that the main cause of the decision-making and construction process delays is a lack of knowledge.

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The magnitude of the net electric field at the center of the square is

5.38799 x 10^4 N/C.

An electric field is described as the physical field that surrounds electrically charged particles and exerts force on all other charged particles in the field, either attracting or repelling them.

Qa = Charge at point

A = −2.4× 10 −12C

Qb = Charge at point

B = 2.4 × 10 −12C

Qc = Charge at point

C = 2.4×10−12C

Q = Charge at point

D = 2.4 ×10−12C

a= side of the square = 4cm = 0.04 m

Ea = magnitude of the electric field at center of the square due to charge

QAEb

= magnitude of the electric field at center of the square due to charge

QBEc

= magnitude of the electric field at center of the square due to charge

QCEd

= magnitude of the electric field at center of the square due to charge

QDE x = Net electric field in X-axis.

Ey

= Net electric field in Y-axis

Magnitude of electric field at distance R due to a charge q = kx q/R^2

Where k = 8.98 X 10^9

Magnitude of net electric field in X-axis is

Ex = Ea×cos45 + Ec × cos45 +Eb × cos45 − Ed × cos45

Ex =

3.80989 × 10^4 N/C (If you substitute values)

Magnitude of net electric field in Y-axis is

Ex = Ea× Sin45 + Ec × Sin45 +Eb × Sin45 − Ed × Sin45

Ex =  5.38799 × 10^4 N/C

Therefore, the magnitude of the net electric field at the center of the square is

5.38799 x 10^4 N/C.

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The work done by the crane in lifting the crate is calculated to be 100 KJ.

Energy is transferred as a gain in the object's gravitational potential energy when work is done to increase the height of the item. Potential energy refers to the work that an object does as a result of its height. An object with mass m at a height h has a gravitational potential energy PE, which is given by the relationship:

PE = m × g × h

where,

m = mass of the object

g = gravitational force acting upon the object

h = height of the object at which it is lifted

Now, it is given that,

Force provided by the crane = mg = 5 KN = 5000 N           (∵ 1kN = 1000N)

Height = 20 m

On substituting the given values in the above relation, we get:

PE = 5000N × 20m

PE = 100000 Joules or 100 kilo Joules

Hence, the work done by the crane in lifting a crate upwards is found to be 100 KJ in the form of potential energy.

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Height h = 20 m and force F = 5 kN are provided.

To Discover: Work Done, W

Work Done, as we are all aware, is the result of force and displacement. Here, we must compute the work performed by the crane in opposition to gravity.

Where,

W = mgh

The mass is m.

Gravitational acceleration, or g,

h is the height the item has gained.

mg = 5 kN for force.

1 kN = 1000 N

As a result, 5 kN equals 5*1000 N.

Replace with the value we obtain

→ W = 5000 × 20

→ W = 100000 J

→ W = 100000/1000 Kj

→ W = 100Kj

As a result, the crane's labour to raise the cargo was 100 KiloJoules.

According to work energy theorem Word Done = Energy Used

Thus, 100KJ is the required amount of Kinetic Energy required by the Crane.

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The acceleration of gravity in the new planet is 0.41 m/s^2.

What is gravitational acceleration?

Gravitational acceleration is the acceleration that an object experiences due to the force of gravity. It is the rate at which an object's velocity changes as it falls toward the center of a gravitational field, such as the Earth or another planet.

The magnitude of gravitational acceleration is often denoted by the symbol "g," and it is equal to the acceleration an object would experience if it were dropped from rest at the surface of the Earth. On the surface of the Earth, g is approximately 9.8 meters per second squared or 1 g. However, the value of g can vary slightly depending on the location and the strength of the gravitational field. For example, g is slightly weaker at the Earth's poles than it is at the equator due to the Earth's slightly oblate shape.

According to the problem:

The acceleration due to gravity on the planet can be determined by the equation:

acceleration = (distance fallen) / (time taken)^2

Substitute 4.07 meters for the distance and 4.97 seconds for the time to determine the acceleration as the following:

acceleration = (4.07 meters) / (4.97 seconds)^2 = 0.41 m/s^2

So the acceleration of gravity on this planet is approximately 0.41 meters per second squared.

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5789.8 W  is the average power of the elevator motor during this period and 1.115 * 10⁴ W this power compare with the motor power when the elevator moves at its cruising speed.

The rate with which the speed and direction of a moving object vary over time. A point a object going straight ahead is pushed when it accelerates or decelerates.

Mass of elevator = 650 kg

Time = 4.50 sec

Speed of the elevator = 1.75 m/s

Calculating the elevator's acceleration is necessary.

Using the acceleration formula

a = vf - vi / t

a = 1.75 / 4.50

a = 0.38 m/s2

(a). We must determine the net force acting on the elevator.

Using the force formula

T = mg + ma

T = m (g +a)

T = 650 (9.8 + 0.38)

T = 6617 N

We must determine the average velocity.

Using the average velocity formula

v' = vf + vi / 2

v' = 1.75 / 2

v' = 0.875 m/s

We must determine the average power.

Using the power formula

P = T * v'

P = 6617 * 0.875

P = 5789.8 W

(b). We must determine the motor's power input.

Using the power formula

P = F * v

P = mg * v

P = 650 * 9.8 * 1.75

P = 1.115 * 10⁴ W.

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Pulling the block at an unknown constant acceleration with the force probe for a measured distance will allow the students to take the measurements needed to calculate the work done by friction. the correct answer is C.

As is common knowledge, the product of force and displacement defines the amount of work done.

hence, it is said as

W =F.d

where,

W is work

F is force

D is displacement

Therefore, in this case, force and displacement must be known in order to determine the work done.

In order to determine the amount of work done, we must first pull the block with a constant acceleration. therefore the correct answer is C

Your question is incomplete but most probably your full question was

Some students want to calculate the work done by friction as an object with unknown mass moves along a straight line on a rough horizontal surface. The students have a force probe, a meterstick, and a stopwatch. Which of the following will allow lo lake the measurements needed to calculate the work done by friction?

(A) Pulling the block at an unknown constant acceleration with the force probe for a measured time.

(B) Pulling the block at an unknown constant speed with the force probe for a measured time.

(C) Pulling the block at an unknown constant acceleration with the force probe for a measured distance.

(D) Pulling the block at an unknown constant speed with the force probe for a measured distance.

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The atmospheric pressure of the sample when depth, density and total pressure is given is 62.5 x 10⁸ Pa.

Atmospheric pressure is defined as a unit of measurement equal to the normalized atmospheric pressure at sea level and 15 °C.  Because it is determined using a barometer, atmospheric pressure is also referred to as barometric pressure.

It can be expressed as

P = hрg

P = 25 x 2.5 x 10⁵ x 1000

P = 62.5 x 10⁸ Pa

Thus, the atmospheric pressure of the sample when depth, density and total pressure is given is 62.5 x 10⁸ Pa.

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The  length of X components is 3,708 and Y component is 11,412

Another method for locating vector components is to use the angle measured in the opposite direction from the +x axis. Then, the x-component will always be cos and the y-component will always be sin.

A vector's rectangular component Ax, Ay, and Az, respectively, are the projections of vector A along the x, y, and z directions. Space coordinates of a point: The triplet (x, y, z) denotes a point's coordinates.

Given ,

x-component

= 12 * cos 72

= 12 * 0,3090

= 3,708

y component

= 12 . sin 75

= 12 . 0,9510

= 11,412

Therefore The  length of X components is 3,708 and Y component is 11,412

The complete question is : What are the lengths of the x and y components of this vector?

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Answer:

The answer is S

Explanation:

Amplitude is defined as the height of a wave from its undisturbed level.

The fundamental mental capacities required to acquire and comprehend any subject have been categorized as fluid intelligence.

Human intelligence includes the abilities to learn from experience, adapt to new situations, understand and manage abstract concepts, and use information to change one's environment. Using longitudinal research designs the same people's behavior is examined over time .  For instance, if we were to examine the connection between intelligence and aging, a scientist might do a longitudinal research to see whether 20-year-olds lose intelligence as they age. Gardner's idea was criticized by Psychologists and teachers. Gardner's concept of intelligence, according to these opponents, is too wide, and his eight different "intelligences" only represent skills, personality traits, and other characteristics.

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The calculated value of angle of refraction be 29.88°.

Refraction is defined as "the change in a wave's direction as it passes through a medium."

Although light refraction is one of the most frequently seen phenomena, refraction can also occur with sound and water waves. We can use optical tools like lenses, prisms, and magnifying glasses thanks to refraction. We can focus light on our retina because of the refraction of light, which is another benefit.

Given that;

Angle of incident of light from air to water: i = 24°

Refractive index of water: n = 1.33

So, the angle of refraction be = sin⁻¹(nsini) = sin⁻¹( 1.33 sin24°) = 29.88°.

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The equilibrium position from the above was the position only at the C.

define equilibrium ?

1. A situation when all acting effects are neutralised by other factors, leaving a system that is stable, balanced, or unchanging.

2. Emotional or mental equilibrium.

3. Physics The state of a body or physical system when it is at rest or moving slowly, during which all forces acting on it result in zero and all torques about all axes add up to zero.

4. Chemistry a. A chemical reaction in which both the forward and reverse reactions proceed at the same rate, preventing a change in the concentration of the reactants and products over time.

b. The condition of a system in which there are several phases and interchange between them happens at equal rates, resulting in a net loss of energy.

The sole position at the C was the equilibrium position from the above.

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The time interval required for the proton to travel 4.50 cm horizontally is  1.07 x 10⁻⁷ s , vertical displacement during the time interval in which it travels 4.50 cm horizontallyis  0.0043 m, and the horizontal and vertical components of its velocity after it has traveled 4.50 cm horizontally_ j km/s.

a. Let t be the amount of time needed for a proton to move 4.50 cm 0.045 m horizontally. It is calculable as follows:

t = d/v

where t is time, d is distance and v is velocity

t= d/v

t = 0.045m / 4.20 x 10⁵ m/s = 1.07 x 10⁻⁷ s

b. because the initial speed in the vertical direction is 0. So,

Thus, q E = ma.

ay= (Ey q)/m

Displacement is given by :

y=ut + 1/2ayt²

y =1/2 ((Ey q)/m) t²

y =(1/2)(7.60 x 10³ N/C x 1.67 x 10⁻¹⁹)(1.07 x 10⁻⁷)²

y= 0.0043 m

c.Use the following kinematics equation for the vertical component of velocity:

V(y)²-u²= 2ayd

[tex]v_y=\sqrt{\frac{E_{y}q}{m}d_{y} } \\v_y=\sqrt{\frac{7.60 X 10^3 N/C _{} X 1.67 x 10^{-19}}{ 1.67 x 10^{-27}} 0.045[/tex]

v=1.8493 X10⁵ m/s

velocity horizontal component,

vₓ =d/t

vₓ= 0.045/( 1.07 x 10⁻⁷ s) = 4.20 x10⁵

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The wavelength of the electron, given that it is travelling at 1.0×10⁷ m/s is higher than that of the ball travelleing at 35 m/s

To compare the wavelength of both the electron and ball, we shall determin the the wavelength of both the electron and ball. Details below:

For electron:

λ = 2h / mv

λ = (2 × 6.626×10⁻³⁴) / (9.1×10⁻³¹ × 1.0×10⁷)

λ = 1.46×10⁻¹⁰ m

For ball:

λ = 2h / mv

λ = (2 × 6.626×10⁻³⁴) / (0.10 × 35)

λ = 3.79×10⁻³⁴ m

From the above calculation we obtained:

Thus, we can conclude that the the wavelength of the electron is higher than that of the ball.

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