A pulley system has an efficiency of 87.5 percent.
How much of the rope must be pulled in if a force of
648 N is needed to lift a 150 kg desk 2.46 m?
(Disregard friction.)

Answers

Answer 1

Answer:

work done on desk = m g h = 105 * 9.81 * 2.46 = 2534 Joules

Explanation:

so work in = 2534 / 0.875 = 2896 Joules

that is your 648 times distance your hand moved holding the rope

2896 = 648 * x

4.47 meters

I think maybe a typo, 648 N is too big, maybe 64.8 ? Any block and tackle system does better than that.


Related Questions

i have to match the words to its definition i have 15 minutes plz

Answers

Time is the 2 one and I’ll put the rest in the comments

A monatomic ideal gas is compressed at a constant pressure of 0.293 atm from a volume of 8.26 L to 3.32 L. In the process, heat energy flows out of the gas. What is the work done on the gas?

Answers

The work done on the gas as it is compressed from volume 1 to volume 2 is 146.7 J.

Given the data in the question;

Pressure; [tex]P = 0.293 atm = 29688.225pa[/tex]Initial volume; [tex]v_1 = 8.26L = 0.00826m^3[/tex]Final volume; [tex]v_2 = 3.32L = 0.00332m^3[/tex]

Work done on the gas; [tex]W = \ ?[/tex]

From the first law of thermodynamic:

[tex]W = -P\delta v[/tex]

Where W is work done, P is pressure and [tex]\delta v[/tex] is  change in volume.

We substitute our values into the equation

[tex]W = -29688Pa * ( 0.00332m^3- 0.00826m^3)\\\\W = -29688Pa * -0.00494m^3\\\\W= 146.7 J[/tex]

Therefore, the work done on the gas as it is compressed from volume 1 to volume 2 is 146.7 J.

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If an astronaut was on a planet 9*10^10 meters away, how long would it take a radio signal (in seconds) to travel from them to Earth? (Be sure to give your answer to two decimal places)

Answers

The time taken a radio signal to travel form the given distance to Earth is [tex]2.65 \times 10^8 \ s[/tex].

The given parameters;

distance between the astronaut and Earth, d = 9 x 10¹⁰ m

The time taken a radio signal to travel form the given distance to Earth is calculated by using Echo formula as shown below;

[tex]2d = v \times t\\\\t = \frac{2d}{v}[/tex]

where;

v is the speed of sound sound in air = 340 m/st is the time taken for the signal to be heard (to and fro)

The time taken for the signal to travel in a single forward motion is calculated as;

[tex]t = \frac{1}{2} \times \frac{2d}{v} = \frac{d}{v} \\\\t = \frac{9\times 10^{10}}{340} \\\\t = 2.65 \times 10^8 \ s[/tex]

Thus, the time taken a radio signal to travel form the given distance to Earth is [tex]2.65 \times 10^8 \ s[/tex].

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Two workers use 100 N of force to move a sofa 2 meters in 2 seconds. How
much power is required?
A. 200 W
B. 100 W
C. 4 W
D. 400W

Answers

Answer:

B.) 100 W

Explanation:

Power = work/time = (Force * Distance)/Time

Force = 100 N

Distance = 2M

Time = 2 sec

Power = (100 * 2)/2 = 100 Watts

Thus the answer is B.) 100 W

An incompressible fluid is flowing through a horizontal pipe with a constriction. The velocity of the fluid in the wide section of the pipe is 5.00 m/s and the velocity of the fluid in the narrow section of pipe is 8.00 m/s. The pressure of the fluid in the wide section is 200 kPa. What is the pressure in the narrow section of the pipe

Answers

The Bermoulli's  equation allows us to find the pressure in the narrow part of the pipe through which water circulates is:

             P = 500 Pa

Bernoulli's equation is the work-energy relationship for fluids that are liquids and gases.

           [tex]P_1 + \frac{1}{2} \rho v_1^2 + \rho g y_1 = P2 + \frac{1}{2} \rho v_2^2 + \rho g y_2[/tex]

Where the subscripts 1 and 2 represent points of interest, P is the pressure, ρ the density of the fluid, v the velocity and y the height.

They indicate that the pipe is horizontal, that the pressure in the wide part P₁ = 200 kPa and the velocity is v₁ = 5 m / s and in the narrow part v₂=8.00 m/s, see attached.

Since the pipe is horizontal y₁ = y₂

           P₁ + ½ ρ v₁² = P₂ + ½ ρ v₂²

           P₂ = P₁ + ½ ρ (v₁² - v₂²)

Let's calculate

          P₂ = 200 10² + ½ ρ (5² - 8²)

          P₂ = 2 10⁴ - 19.5 ρ

For a specific calculation the value of the density of the fluid is needed, suppose that the fluid is water ρ = 1000 kg / m³

           P₂ = 2 10² - 19.5 1000

           P₂ = 500 Pa

In conclusion using the Bermoulli equation we can find the pressure in the narrow part of the pipe through which water circulates is:  

             P = 500 Pa

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Accelerating car is a _______

•Law of inertia
•Law of universal gravitation
•Law of acceleration
•Law of conversation of energy​

Answers

Acceleration is the rate of change of velocity as a function of time. For example a car traveling at 50 km/hr starts to accelerate, 10 seconds after, its speed changes to 100 km/hr then the acceleration of the car during the time can be calculated as below: initial speed = 50 km/hr.

Answer: C.
Hint on to of why this is correct “ACCELERATING a car” glad I can help :)

Compare and contrast the different parts of the Electromagnetic Spectrum. Evaluate the usefulness of each part and decide which part is most useful, or most important, to you and society as a whole. You must provide two reliable sources to back up your opinion. Recall that reliable sources include scientific sites or publications, education sites or publications, and government sites or publications.

Answers

Answer:

Think in your Mind

Explanation:

if you do you will have a better understanding of what you're doing

you could study you could ask a parent or guardian

or maybe stop looking up answer and expect other people breaking thier heads doing this

In a chemical reaction, two molecules with a total mass of 76 amu react to form a single molecule. What is the mass of the molecule that is formed?

FIRST ANSWER GET EVERYTHING IN THE JOVID SUPPORT PACKAGE! :)

Answers

Answer:

The total number of atoms does not change, so mass is conserved in the reaction

So answer is 76

Explanation:

If you like my answer than please mark me brainliest thanks

In a chemical reaction, two molecules with a total mass of 76 amu react to form a single molecule. The mass of the molecule that is formed is equal to that of the total mass of two molecules which is 76 amu.

What is a Chemical reaction?

A chemical reaction may be defined as a type of reaction in which two or more molecules are combined as reactants in order to form a new compound which is known as a product.

In this question, according to the law of conservation of mass, mass can neither be created nor be destroyed in a given chemical reaction. So, if the total mass of two reactant molecules is 76 amu, then the resultant product also bears the same mass.

Therefore, the mass of the molecule that is formed is equal to that of the total mass of two molecules which is 76 amu.

To learn more about the law of conservation of mass, refer to the link:

https://brainly.com/question/15289631

#SPJ5

PLEASE HELPPPPPPPPPP

Answers

Answer:

sorry me computer is blocking the picture but i will try to unblock so i can answer

Explanation:

Q1: Calculate the diameter of a copper conductor 300 m long such that it may carry 500 A with a voltage drop of 8 V. The resistivity of the copper may be taken as 0.019  m.

Answers

The diameter of a copper conductor is equal to 21.30 meters.

Given the following data:

Length = 300 mCurrent = 500 A Voltage = 8 VResistivity = 0.019

To calculate the diameter of a copper conductor:

First of all, we would determine the resistance of the copper conductor by using the formula:

[tex]Resistance = \frac{Voltage }{Current} \\\\Resistance =\frac{8}{500}[/tex]

Resistance = 0.016 Ohms

Next, we would determine the area of the copper conductor:

[tex]Resistance = \frac{\rho l}{Area} \\\\Area = \frac{\rho l}{Resistance}\\\\Area = \frac{0.019 \times 300}{0.016}[/tex]

Area = 356.25 [tex]m^2[/tex]

For the diameter:

From the area of a circle, diameter is given by the formula:

[tex]Area = \frac{\pi d^2}{4} \\\\d=\sqrt{\frac{4A}{\pi} } \\\\d=\sqrt{\frac{4 \times 356.25}{3.142} }\\\\d=\sqrt{453.53}[/tex]

Diameter, d = 21.30 meters

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One type of BB gun uses a spring driven plunger to blow the BB from its barrel. Calculate the force constant of its plunger's spring if you must compress it 0.150 m to drive the 0.0500 kg plunger to a top speed of 20.0 m/s.

Answers

Answer:

a) 889 N / m

b) 133 N

A 3.6-kg goose floats on a lake with 46 % of its body below the 1000-kg/m3 water level. Determine the average density of the goose.

Answers

The average density of the goose on the given lake is 460 kg/m³.

The given parameters;

mass of the goose, m = 3.6 kgfraction of the goose below the lake, = 46%density of the water, ρ = 1000 kg/m³

The specific gravity of the goose is calculated as follows;

[tex]S.G = \frac{46}{100} = 0.46[/tex]

The density of the goose is calculated as follows;

[tex]S.G = \frac{\rho _{g}}{\rho_{w}} \\\\\rho_{g} = S.G \times \rho_{w}[/tex]

where;

[tex]\rho _{w}[/tex] is the density of water[tex]\rho _{g}[/tex] is the density of the goose

The density of the goose is calculated as;

[tex]\rho _{g}= 0.46 \times 1000 \ kg/m^3\\\\\rho _{g}= 460 \ kg/m^3[/tex]

Thus, the average density of the goose on the given lake is 460 kg/m³.

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Help please its 30 marks thanks for willing to help me

Answers

Answer:

Independent variable: Height

Dependent variable: time

Explanation:

Not sure what the experiment was, but assuming that this was the amount of time for a ball to reach the ground, the independent variable would be height since you determine and change the initial height. The dependent variable would be time since it changes with height, and you have to measure it.

A photograph of you and your friends at your 8th birthday party.is it secondary or primary source and why?

Answers

Answer:

primary source

Explanation:

the explanation is in the image above

brainliest please

can anyone heelp me plzz

Answers

Answer:

the ans is D... good luck

how do organisms interact with the living and the non-living environment to obtain matter and energy?​

Answers

Answer:

Seeking matter and energy resources to sustain life, organisms in an ecosystem interact with one another in complex feeding hierarchies of producers, consumers, and decomposers, which together represent a food web.

can anyone heelp me plz plz

Answers

Answer:

the ans is D.... good luck

Awnser is D hope this helped

F = kx
k = ?
Select one:
a. F/x
b .x/F
c. F + x
d. F − x

Answers

Answer:

[tex]F = kx \\ k = \frac{F }{x} [/tex]

so the answer is a

NO LINKS Select the choice that shows the helping verb followed by the main verb. I am writing this sentence. I am writing this sentence. I am writing this sentence. I am writing this sentence​

Answers

The helping verb in the sentence; "I am writing this sentence" is the verb "am".

Helping verbs are verbs that occur in sentences or clauses whose function is to express tense, form negations or form a question. Examples of helping verbs include; Am, is, are, was and were, being, been, and be, Have, has, had, do, does, did, will, would, shall and should, may, might, must, can, could.

In this sentence; "I am writing this sentence", the helping verb is "am". It helps to express the tense of the action that is being carried out.

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Two projectiles are thrown with the same initial velocity, one at an angle and the other at an angle of . (a) Can both projectiles strike the ground at the same distance from the projection point? (b) Can both projectiles be in air for the same time interval?​

Answers

Answer:

si quiero ser tu novia❤❤

Forces can...
A. Change speed of motion
B. Change shape of objects
C. Change direction of motion
D. All of the above

Answers

Answer:

D

Explanation:

Forces can change speed of motion, the more force that's applied when you push a ball for example, the faster the ball will go. Force can also change the shape of objects by applying pressure to them too. The inertia from force can change direction, as when you let's say hit a tennis ball, it won't go perfectly straight. So all of the above are correct

HELP

If a car is traveling at constant speed of 70 kilometers per hour, how many hours will it take for the car to travel a distance of 28 kilometers

If a car is traveling at constant speed of 100 kilometers per hour, how many hours will it take for the car to travel a distance of 280 kilometers ?

If the velocity of a caer changes from 0 meters per second to 100 meters per second in 10 seconds, what is the acceleration over that 10 second period?

If the velocity of a caer changes from 20 meters per second to 60 meters per second in 4 seconds, what is the acceleration over that 4 second period ?

Answers

Answer:

Explanation:

28 / 70 = 0.3857142...  = 0.39 hr

280 / 100 = 2.8 hrs.

(100 - 0) / 10 = 10 m/s²

(60 - 20) / 4 = 10 m/s²

A 20 kg block (4) rests on a frictionless table;
a cord attached to the block extends
horizontally to a pulley at the edge of the
table. A 10 kg mass (B) hangs

Answers

Answer:

Explanation:

F = ma

a = F/m

a = 10(9.8) / (10 + 20)

a = 3.3 m/s²

(T)ension in the cord

20(3.3) = 65 N

A man moves a box horizontally by exerting on it a force of 90 N directed at 60 above the horizontal. If the work done on the box is 450 J, the displacement of the box is

Answers

Hi there!

We know that:

W = F · dcosФ

The cosine indicates that work only takes into account the component of the force that is parallel to the displacement.

Thus, we must find the horizontal component of the force:

FcosФ = horizontal component

90cos(60) = 45 N

Now, we can solve for displacement:

W = Fd

W/F = d

450/45 = d = 10 m


A hooligan throws a stone vertically down with an initial speed of 17 m/s from the roof of a building 51 metres above the
ground. How long in seconds does it take the stone to reach the ground?

Answers

Answer:

Explanation:

impact velocity is

√(18² + 2(-9.8)-51) = 36 m/s

average velocity is (17 + 36)/2 = 26.5 m/s

t = d/v = 51 / 26.5 = 1.9 s

or

if ground is origin and UP positive

0 = 51 - 17t - ½(9.8)t²

quadratic formula

t = (17 ±√(17² - 4(-4.9)(51))) / (2(-4.9))

t = (17 ± 36) / -9.8

t = - 5.4 s which we ignore as the stone is not thrown yet

or

t = 19 s

en que consiste el atletismo de pista y campo?

Answers

Answer:

El atletismo es un deporte que incluye competencias atléticas basadas en las habilidades para correr, saltar y lanzar. El nombre se deriva del lugar donde se lleva a cabo el deporte, una pista de atletismo y un campo de hierba para los lanzamientos y algunos de los eventos de salto.

Explanation:

Yo se esto

I HAVE NOOOO IDEA!!!!!!!!!! HELP!!!!!!!!!!


Use the equation for motion to answer the question.

x=x₀+ v₀t + 1/2at²

An object has a starting position of 2 m, a starting velocity of 15 m/s, and is moving at a constant speed. Which option shows the final position of the object after 1 s?

A. 30 m

B. 60 m

C. 32 m

D. 17 m

Answers

Answer:

17

Explanation:

How is an interference pattern formed by a diffraction grating different from the pattern formed by a double slit

Answers

Answer:

Evaluate the following numerical expressions.

6 + 3 • 4 =

18

(6 + 3) ÷ (4 – 5) =

Explanation:

Evaluate the following numerical expressions.

6 + 3 • 4 =

18

(6 + 3) ÷ (4 – 5) =

How does the drop height (gravitational potential energy) of a
ball affect the bounce height (kinetic energy) of the ball?
The

Answers

If the drop height increases, then the resulting bounce height will also increase, because as the drop height increases, so does the gravitational potential energy which can be converted back into kinetic energy on the rebound.

A bullet (m=20g) shot with a speed of 800 m/s hits an oak tree and sticks 4cm inside it.
What is the average force acting on the bullet from the tree?

Answers

Hi there!

We can begin by converting cm to m:

4cm = 0.04 m

Use the following equation:

vf² = vi² + 2ad

The final velocity is 0 m/s, so:

0 = vi² + 2ad

vi² = -2(a)d

Plug in given values to solve for the acceleration:

800²/2(0.04) = -a

a = -8,000,000 m/s²

Find the force using the equation:

F = ma

F = (0.02)(-8,000,000) = -160,000 N

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