A block and tackle machine is used to raise 300 kg grand piano a vertical distance of 12.5 m. If the efficiency of the block and tackle machine is 0.80, how much work must the piano movers do in lifting the piano ? a. 45938 J b. 36750 J c. 29400 J d. 4688 J

Answers

Answer 1

The amount of work done by the piano mover in lifting the piano 45938 J (Option A)

What is efficiency?

This can be defined as the capacity to achieve a given task with little or no waste. Mathematically, it can be expressed as

Efficiency = (output / input) × 100

How to determine the work inputMass (m) = 300 KgDistance (s) = 12.5 mEfficiency = 0.80Acceleration due to gravity (g) = 9.8 m/s²Output = mgs = 300 × 9.8 × 12.5 = 36750 JInput = ?

Efficiency = output / input

Input = Output / efficiency

Input = 36750 / 0.8

Input = 45938 J

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Answer 2
A
because it’s A lol

Related Questions

A crowbar with the length of 200 cm is used to lift the load of 600 Newton . If the distance between fulcrum and load is 0.75 . Calculate Effort , Mechanical advantage and Velocity ratio

Answers

Answer:

a. Effort = 960 Newton

b. Mechanical advantage (M.A) = 0.625

c. Velocity ratio (V.R) = 1.67

Explanation:

Given the following data;

Load = 600 N

Length of crowbar = 200 cm

Length of load arm = 0.75 m

Conversion:

100 cm = 1 m

X cm = 0.75 m

Cross-multiplying, we have;

X = 0.75 * 100 = 75 cm

First of all, we would find the effort arm;

Effort arm = length of crow bar - length of load arm

Effort arm = 200 - 75

Effort arm = 125 cm

Next, we would determine the mechanical advantage (M.A) of the crow bar;

Substituting the values into the formula, we have;

M.A = 0.625

To find the effort of the crow bar;

Making "effort" the subject of formula, we have;

Effort = 960 Newton

Lastly, we would determine the velocity ratio (V.R);

V.R = 1.67

Answer:a. Effort = 960 Newton

b. Mechanical advantage (M.A) = 0.625

c. Velocity ratio (V.R) = 1.67

Explanation:

Two identical negative charges exert a repellent force of 150 N on each other when they are 40 cm apart. that is the magnitude of each negative charge?
a. 2.7 nC
b. 51.6 microC
c. 0.67 microC
d. 0.82 mC

Answers

The final answer is 51.6 microC which is answer choice b:
The magnitude of each negative charge is 51.6 microC

Why would an object have a much lower maximum speed falling through water than falling through air?

Answers

The exact same principles of physics are involved regardless of the medium through which an object is falling.

That said, which particular principles are having the most effect may change. In air, for example, drag matters more than buoyancy for most solid objects, but in water this can be reversed, at least for objects that have any significant buoyancy to begin with.

No matter how you slice it, however, the same principles apply in all cases where terminal velocity applies, i.e. not in empty space.

Answer:

Explanation:

when objects move through a fluid such as air or water the fluid exerts a frictional force on the moving object. the frictional force from fluid is called a drag force friction drag force causes objects to slow down as they move through a fluid such as air or water.

100 POINTS+BRAINLIEST: 8TH GRADE SCIENCE - EVAPORATION VS VAPORIZATION: is option B actually wrong? Because vaporization involves a solid OR liquid turning into a gas above BP, while evaporation is when liquid turns into gas below the BP (boiling point). If I'm wrong please explain why -Thanks!!!!

Answers

Answer:

Explanation:

Vaporization occurs during the boiling/sublimation process. That is the only reason why I could see this being marked as wrong.

Answer:

Explanation:

yes it is wrong vaperation only occurs during the boiling process

Using the formula for work, Match the Force × Distance problems with their correct "Work Performed" answer. The first example has been completed for you.

Force × Distance = Work Performed

10 newtons 6 meters =60 Nm

1. 62 Nm
40 pounds 100 feet

2. 4000ft.-lbs.
2.5 pounds 24 inches

3. 5 ft.-lbs
62 newtons 1 meter

4. 200ft.-lbs.
1 ton 20 feet

5. 40,000 ft.-lbs.
400 pounds 0.5 feet

Answers

1. 62NM = 62 newtons 1 meter
2. 4000ft.-lbs = 40 pounds 100 feet
3. 5ft.-lbs = 2.5 pounds 24 inches
4. 200ft.-lbs = 400 pounds 0.5 feet
5. 40,000 ft.-lbs = 1 ton 20 feet
1. 62NM = 62 newtons 1 meter
2.4000ft.-Ibs = 40 pounds 100 feet
3. 5ft.-ibs = 2.5 pounds 24 inches
4. 200ft.-Ibs = 400 pounds 0.5 feet
5. 40,000 ft.-Ibs = 1 ton 20 feet

Can someone tell me what's the formular for extension? Thank youu ​

Answers

Answer:

F = ke

Explanation:

F is the applied force.

k is the spring constant.

And e is extension.

It can be re-arranged as k=F/e or e=F/k. It is Hooke's law.

F = ke is the formula for the extension.

When an object's length rises, extension occurs, and when it reduces, compression occurs. Hooke's law states that force applied by a spring equals extension minus the spring constant. This law describes the extension of an elastic item, such as a spring.

The lengthened portion of an object, such as a spring, is known as its extension. According to Hooke's law, as long as the limit of proportionality is not crossed, a spring's extension is directly proportionate to the force exerted.

F = ke

F is the applied force.

k is the spring constant.

And e is an extension.

It can be re-arranged as k=[tex]\frac{F}{e}[/tex] or e=[tex]\frac{F}{K}[/tex]. It is Hooke's law.

Understanding the behavior of the material as it is stretched or compressed requires knowledge of Hooke's law. By comprehending the material behavior features, technology can be improved.

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(1.) When aqueous solutions of Fe(NO3)3 and NaOH are mixed, Fe(OH)3 and NaNO3 are formed. is there a precipitate formed? if yes, write the formula for the precipitate and explain why it is the precipitate using the solubility rules. (2.) When aqueous solutions of potassium iodide and Lead (II) nitrate are combined, potassium nitrate and solid lead (II) iodide are formed. Write the balanced,complete ionic and net ionic equations for this reaction

Answers

From the solubility rules, both reactions 1 and 2 lead to precipitates.

What is a precipitate?

The term precipitate refers to the solid that separates out of the reaction mixture . We know that the solubility of a substance in water is predicated on the solubility rules.

1) The reaction here is;

Fe(NO3)3(aq) +  3NaOH(aq) ------> Fe(OH)3(s) + 3NaNO3(aq) - The precipitate is  Fe(OH)3 because only the hydroxides of group 1 elements are soluble in water.

2) The reaction is;

Pb(NO3)2(aq) + 2KI(aq) ----->PbI2(s) + 2NaNO3(aq) - The precipitate is PbI2 because most iodides are soluble except the iodides of  Ag+, Hg+2, and Pb+2

Complete Ionic equation;

Pb^2+(aq) + 2NO3^-(aq) + 2K^+(aq) + 2I^-(aq) ------> PbI2(s) +  2NO3^-(aq) + 2K^+(aq)

Net ionic equation;

Pb^2+(aq) + 2I^-(aq) ------> PbI2(s)

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(1.) Consider the equation: 4Fe + 3O2 yields 2Fe2O3
- What is the theoretical yield of Fe2O3 when 12.0g of iron rusts?
- If 14.21 g of Iron (III) oxide is actually produced what is the percent yield ?

(2.) what is the molarity of a 126.81 L solution that contains 5.1 moles of KCl ?

Answers

1a. The theoretical yield of Fe₂O₃ obtained is 17.14 g

1b. The percentage yield of Fe₂O₃ obtained is 82.9%

2. The molarity of the KCl solution is 0.04 M

1a. How to determine the theoretical yield of Fe₂O₃

Balanced equation

4Fe + 3O₂ —> 2Fe₂O₃

Molar mass of Fe = 56 g/mol

Mass of Fe from the balanced equation = 4 × 56 = 224 g

Molar mass of Fe₂O₃ = (56×2) + (16×3) = 160 g/mol

Mass of Fe₂O₃ from the balanced equation = 2 × 160 = 320 g

SUMMARY

From the balanced equation above,

224 g of Fe reacted to produce 320 g of Fe₂O₃

Therefore,

12 g of Fe will react to produce = (12 × 320) / 224 = 17.14 g of Fe₂O₃

Thus, the theoretical yield of Fe₂O₃ is 17.14 g

1b. How to determine the percentage yield Actual yield of Fe₂O₃ = 14.21 gTheoretical yield of Fe₂O₃ = 17.14 gPercentage yield of Fe₂O₃ =?

Percentage yield = (Actual / Theoretical) × 100

Percentage yield of Fe₂O₃ = (14.21 / 17.14) ×100

Percentage yield of Fe₂O₃ = 82.9%

2. How to determine the molarity of the KCl solutionMole of KCl = 5.1 molesVolume = 126.81 LMolarity of KCl =?

Molarity = mole / volume

Molarity of KCl = 5.1 / 126.81

Molarity of KCl = 0.04 M

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What is the first stage of metamorphosis?

Adult
Egg
Larva
Nymph

Answers

egg it then moves to the second stage larva
Egg! The eggs are laid by the female insect. Then later on hatch going into other stages.

What type of presentation us easier to plan using a site map?



A. a presentation that lets users link our from a “home” page or slide

B. an animation created digitally using a program like Flash

C. a slide show that starts on slide one and goes slide by slide to the end

Answers

Answer:

I believe that the answer would be A

Explanation:

because there is all of the examples I found online have a home page.

What type of presentation us easier to plan using a site map?



A. a presentation that lets users link our from a “home” page or slide

(1.) A 0.5 kg basketball rolls off the roof of a building. At a moment when it is 3 m above the ground, it has a speed of 2.5 m/s. What is the total mechanical energy of the basketball ?
(2.) In the previous problem, how much kinetic energy does the football possess just after the throw? Assume that the football started from rest.

Answers

Answer:

The answer is C.

Explanation:

Since the total mechanical energy is conserved, kinetic energy (and thus, speed) will be greatest when the potential energy is smallest.

I believe the answer is c

(1) A positive charge +3 C is separated from another positive charge of +5 C by a distance of 7m. What is the magnitude of the electric force between the two charges?

(a.) 1.9 × 10 to the 10th power N (b.) 2.8 × 10 to the 9th power N (c.) 2.1 N (d.) 0.31 N

(2) A molecule has 223 electrons and 218 protons. what is the net charge on the molecule ? (a.) 5 × 10 the the - 19th power C (b.) - 5 × 10 to the - 19th power C (c.) 8 × 10 to the - 19h power C (d.) -8 × 10 to the - 19th power C


(3) A negative charge of 2 × 10 to the negative 4 C and a positive charge of 8 × 10 to the negative 4 C are separated by a distance of 0.3 m. what is the magnitude of the force between the charges? (a.) 4800 N (b.) 1.78 × 10 to the - 6th power N (c.) 16000 N (d.) 0.001 N


(4) Which one of these statements is true of a neutral or charged object?

(a.) A neutral object does not have any charged particles in it.

(b.) A neutral object does not have any protons or electrons in it.

(c.) A neutral object has equal numbers of protons and electrons.

(d.) The protons and electrons in a neutral object do not have any charge.

THEY ARE ALL SEPARATE QUESTIONS
THANK YOU

Answers

1. The magnitude of the electric force between the two charges is 2.8×10⁹ N (Option B)

2. The net charge on the molecule is -8×10⁻¹⁹ C (Option D)

3. The magnitude of the force between the charges is 16000 N (Option C)

4. The correct statement is: A neutral object has equal numbers of protons and electrons. (Option C)

1. How to determine the forceCharge 1 (q₁) = +3 CCharge 2 (q₂) = +5 CElectric constant (K) = 9×10⁹ Nm²/C²Distance apart (r) = 7 mForce (F) =?

F = Kq₁q₂ / r²

F = (9×10⁹ × 3 × 5) / (7)²

F = 2.8×10⁹ N

2. How to determine the net charge on the moleculeElectron = 223 electronsProton = 218 protonsNet Charge =?

Charge = Proton - Electron

Charge = 218 - 223

Charge = -5 electrons

But

1 electron = 1.6×10⁻¹⁹ C

Thus,

Net Charge = -5 × 1.6×10⁻¹⁹ C

Net Charge = -8×10⁻¹⁹ C

3. How to determine the forceCharge 1 (q₁) = 2×10⁻⁴ CCharge 2 (q₂) = 8×10⁻⁴ CElectric constant (K) = 9×10⁹ Nm²/C²Distance apart (r) = 0.3 mForce (F) =?

F = Kq₁q₂ / r²

F = (9×10⁹ × 2×10⁻⁴ × 8×10⁻⁴) / (0.3)²

F = 16000 N

4. What is a neutral object?

A neutral object is an object having equal numbers of protons and electrons. For example, an object with 4 protons and 4 electrons is said to be neutral as illustrated below

Electron = 4 electronsProton = 4 protonsNet Charge =?

Charge = Proton - Electron

Charge = 4 - 4

Charge = 0 (neutral)

Thus, the correct statement about neutral object, given in the question is: A neutral object has equal numbers of protons and electrons (Option C)

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Your answer is 2. A molecule has 223 electrons and 218 protons
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