Kevin used a pulley to lift a piano to the third floor of his apartment. His input work was 12,000 J and the output work was 10,000 J. What was the mechanical efficiency of the pulley?

A . 50%
B. 83.3%
C . 120%
D. 16.7%

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The units of supplementary quantities are dimensionless units.

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Answer:

Explained below

Explanation:

Generally speaking, we know in physics that Electric field lines are lines which usually start at positive charges and deflect away from them to terminate at the negative charges. Meanwhile Equipotential lines are lines that are used to connect points located on the same electric potential.

Finally, in conclusion, electric field lines are usually lines that go through in a perpendicular manner across every equipotential lines.

Answer:

2000g

Explanation:

volume=mass/density

=2000/2.5

=800cm³

mass=density×volume

=800×2.5

=2000g

Answer:

Q = Q

mcT = ml

100 x 4.2 x 25 = (50-18) l

l = 328

*Hope it helps*

The specific latent heat of fusion of the melted ice is 328.13 J/kg.

The specific latent heat of fusion of the melted ice is determined by applying the principle of conservation of energy as shown below;

Heat lost by the water = Heat gained by the ice

McΔθ = mL

where;

(100)(4.2)(25) = (32)L

32L = 10500

L = 328.13 J/kg

Thus, the specific latent heat of fusion of the melted ice is 328.13 J/kg.

Learn more about heat capacity here: https://brainly.com/question/16559442

Answer:

55

Explanation:95-40=55

i hope i did the math right if i didnt please tell me

Answer:

6.9 m/s

Explanation:

1000m = 1km

3600s = 1hr

25000m/3600s

6.9m/s

Answer:

C.

Explanation:

Force = Mass * Acceleration

So 20 = 5* Acceleration

4 = Acceleration

The acceleration of the object is 4 m/s².

To find the acceleration, the given values are:

Force = 20 N

Mass = 5 kg

Definition:

     As it was given as the values of  Force and mass, here acceleration definition depends on the Newton's second law of motion.

Using the second law of motion, the force will be equal to the product of the mass and the acceleration.

As formula,

                               F = ma Newton

Here, to find acceleration,

                              a =f/ m

Substituting the values,

                              = 20 / 5

                            a = 4m/s².

So, the acceleration was 4 m/s². The Option C is the correct answer.

Learn more about acceleration,

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Answer:

The brightness of a light depends on the amplitude of the light wave, which is the extent the waves moves from their equilibrium position. The brightness is also related to the amount of light that is emitted or reflected by an object

Therefore, compared to dim light, light that look bright have a higher amplitude and emit or reflect more light energy (photons)

Explanation:

Answer:

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=quality of life is directly determined by health ,education ,and life expectacy

=health Is a type of thing that gives employment to the person working in firm

hope u understand

Explanation:

Answer:

1028 slits/mm

Explanation:

We are given that

Wavelength of light, [tex]\lambda=530nm=530\times 10^{-9} m[/tex]

1nm=[tex]10^{-9} m[/tex]

[tex]\theta=33^{\circ}[/tex]

n=1

We have to find the number of slits per mm are marked on the grating.

We know that

[tex]dsin\theta=n\lambda[/tex]

Using the formula

[tex]dsin33^{\circ}=1\times 530\times 10^{-9}[/tex]

[tex]d=\frac{530\times 10^{-9}}{sin33^{\circ}}[/tex]

[tex]d=9.731\times 10^{-7} m[/tex]

1m=[tex]10^{3}mm[/tex]

[tex]d=9.731\times 10^{-7}\times 10^3[/tex]mm

[tex]d=0.0009731mm[/tex]

Number of slits=[tex]\frac{1}{d}[/tex]

Number of slits=[tex]\frac{1}{0.0009731}[/tex]/mm

Number of slits=1028/mm

Hence, 1028 slits/mm are marked on the grating.

Answer:

1027.6 lines per mm.

Explanation:

wavelength = 530 nm

order, m= 1

Angle = 33 degree

Let the slits per mm is 1/d.

So,

[tex]m \lambda = d sin A\\\\1\times 530\times 10^{-6} = d sin 33\\\\\frac{1}{d} = 1027.6 lines per mm[/tex]

Answer:

The goal of physics is to understand how things work from first principles. ... Courses in physics reveal the mathematical beauty of the universe at scales ranging from subatomic to cosmological. Studying physics strengthens quantitative reasoning and problem solving skills that are valuable in areas beyond physics.

Answer:

Solids can hold their shape because their molecules are tightly packed together. ... Atoms and molecules in liquids and gases are bouncing and floating around, free to move where they want. The molecules in a solid are stuck in a specific structure or arrangement of atoms

Hope this helps ☆*:. o(≧▽≦)o .:*☆

At the ball's highest point, it has no vertical velocity, so the 6 m/s is purely horizontal. A projectile's horizontal velocity does not change, which means the ball was initially thrown with speed v such that

v cos(53°) = 6 m/s   ==>   v = (6 m/s) sec(53°) ≈ 9.97 m/s

The player shoots the ball from a height of 2.0 m, so that the ball's horizontal and vertical positions, respectively x and y, at time t are

x = (9.97 m/s) cos(53°) t = (6 m/s) t

y = 2.0 m + (9.97 m/s) sin(53°) t - 1/2 gt ²

Find the times t for which the ball reaches a height of 3.00 m:

3.00 m = 2.0 m + (9.97 m/s) sin(53°) t - 1/2 gt ²

==>   t ≈ 0.137 s   or   t ≈ 1.49 s

The second time is the one we care about, because it's the one for which the ball would be falling into the basket.

Now find the distance x traveled by the ball after this time:

x = (6 m/s) (1.49 s) ≈ 8.93 m

Answer:

c

Explanation:

Answer:

900 windings

Explanation:

Applying,

Vs/Vp = Ns/Np............. Equation 1

Where Vs = Secondary voltage, Vp = primary voltage, Ns = Number of turns in the secondary circuit, Np = number of turns in the primary circuit

make Ns the subject of the equation

Ns = VsNp/Vp........... Equation 2

From the question,

Given: Vs = 240 V, Np = 300 windings, Vp  = 80 V

Substitute these values into equation 2

Ns = (240×300)/80

Ns = 900 windings

Answer:

a. X: Slower in gases than liquids Y: Faster in solids than gases Z: Velocity depends on medium.

Explanation:

Speed of sound is fastest in solids. Sound waves travel more quickly in solid, than of liquid and gases. Sound waves travel most slowest in gases. Speed of sound varies significantly and it depends upon medium it is travelling through.  In more rigid medium sounds velocity will be faster.

Answer:

The heat capacity of a body is defined as the heat required to raise it's temperature by me degree or one kelvin.while specific heat capacity of a substance is defined as the heat required to the temperature of a unit mass of it through one degree or one kelvin.

I hope it helps

Answer:

:) :::::::::::::::::::::::::::::::))))

Answer:

increase

Explanation:

guesshejwoowsnnsnakalalapqjhdjd

Answer:

our weight would decrease.

Explanation:

because of you burning all those calories and fat from hiking up the mountain.

Answer:

(a) 37.5 kg

(b) 4

Explanation:

Force, F = 150 N

kinetic friction coefficient = 0.15

(a) acceleration, a = 2.53 m/s^2

According to the newton's second law

Net force = mass x acceleration

F - friction force = m a

150 - 0.15 x m g = m a

150 = m (2.53 + 0.15 x 9.8)

m = 37.5 kg

(b) As the block moves with the constant speed so the applied force becomes the friction force.

[tex]F = \mu m g \\\\150 = \mu\times 37.5\\\\\mu = 4[/tex]

Answer:

C. C

Explanation:

A wave can be defined as a disturbance in a medium that progressively transports energy from a source location to another location without the transportation of matter.

In Science, there are two (2) types of wave and these include;

I. Electromagnetic waves: it doesn't require a medium for its propagation and as such can travel through an empty space or vacuum. An example of an electromagnetic wave is light.

II. Mechanical waves: it requires a medium for its propagation and as such can't travel through an empty space or vacuum. An example of a mechanical wave is sound.

A crest can be defined as the highest (vertically) point on a waveform.

On a related note, a trough is the lowest (vertically) on a waveform.

An amplitude can be defined as a waveform that's measured from the center line (its origin or equilibrium position) to the bottom of a trough or top of a crest. Thus, the vertical axis (y-axis) is the amplitude of a waveform i.e it's measured vertically.

In this scenario, waveform C which is represented by a blue curvy line has the smallest amplitude in comparison with the other waveforms because it has the minimum height when measured from the origin.

In contrast, waveform A represented by a purple line has the highest amplitude because it has the maximum height when measured from the origin.

Mathematically, the amplitude of a wave is given by the formula;

x = Asin(ωt + ϕ)

Where;

Answer:

The answer is indeed D as the comment above suggests.

Explanation:

Simply put, wave D's highest point is closer to the line than all of the other high points of A, B and C

Magnetic force between the north poles of two magnets is REPULSIVE

Answer:Repulsion or attraction

Explanation:The angle between the compass needle   and geographic north is called the MAGNETIC DECLINATION.(see earth:the magnetic field of the earth ). The repulsion or attraction between two magnetic dipoles can be viewed as the interaction of one dipole with the magnetic field produced by other dipole.

Answer:

1. These lines are addressed to Duke.

2. These lines show that Shylock is not willing to forgive the debt a merchant owes him, nor is he willing to justify why he demands that debt be paid, even if it seems cruel.

3. He swore by the Holy Sabbath, which is a holy day for him, who is a Jew. He swore he would get the debt money or a piece of the debtor's flesh.

Explanation:

The lines shown in the question above refer to "The Merchant of Venice" written by Shakespeare. In this story we are introduced to Antonio, a commercial who is very prejudiced against Jews, but when he needs money, he borrows from another merchant, Shylock, who is Jewish. Shylock agrees to lend money to Antonio, but determines the date that this money must be returned, in addition, Shylock states that he will lend the money if Antonio agrees that if this money is not paid by the specified date, Antonio will have to pay with half a kilo of flesh from his own body. Antonio agrees, but doesn't pay the money so Shylock goes after the flesh of Antonio's body and Duke tries to intervene because he thinks this is too cruel. At this point, Shylock speaks the lines shown in the question above, showing that he is not willing to change his mind.

Answer: Symbol is I and unit A

Explanation: A represents Amperes

HOPE THIS HELPS!!!!!!!!

Answer:

The image is formed at 0.44 m in front of the mirror

magnification (M) = 0.44

Explanation:

Applying, mirror formular

1/f = (1/u)+(1/v).................... Equation 1

Where f = Focal length of the convex mirror, u = object distance, v = image distance.

Using the real is positive convection,

From the question,

Given: f = -1.6/2 = -0.8 m( The focal length of a convex mirror is vitual), u = 1.0 m

Substitute these values into equation 1

-1/0.8 = (1/v)+(1/1)

Solve for v

1/v = 1.25+1

1/v = 2.25

v = 1/2.25

v = 0.44 m

Hence the image is formed at 0.44 m in front of the mirror

Magnification (M) = v/u

m = 0.44/1

m = 0.44

Answer:

The maximum height reached is 413.27 m.

Explanation:

How long will it take for a body to reach its maximum height, knowing that it was thrown, vertically upwards, with a velocity whose value was 90 m / s?

initial velocity , u = 90 m/s

gravity, g = 9.8 m/s^2

Let the maximum height is h.

At maximum height the velocity v = 0

Use third equation of motion

[tex]v^2 = u^2 - 2 gh\\\\0 = 90\times 90 - 2 \times 9.8 \times h\\\\h = 413.27 m[/tex]

Answer:

The boiling point of liquids always increases when pressure is applied on a liquid. This is because the molecules of a liquid will need more energy to turn into a gaseous state when pressure is applied on that substance.