In order for work to be done on an object, what must happen to the object?

QUESTION POSTED AT 09/10/2019 - 11:05 PM

Answered by answersmine AT 09/10/2019 - 11:05 PM

The object must get displaced ( change in position ) due to any external force.

W = Fd ( scalar form )  

There are other types of work that can be done on an object. 
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Related questions

A sample of compressed methane has a volume of 648 mL at a pressure of 503 kPa. To what pressure would the methane have to be compressed in order to have a volume of 216 mL?

 To solve this we assume that the gas is an ideal gas. Then, we can use the ideal gas equation which is expressed as PV = nRT. At a constant temperature and number of moles of the gas the product of PV is equal to some constant. At another set of condition of temperature, the constant is still the same. Calculations are as follows:

P1V1 =P2V2

P2 = P1 x V1 / V2

P2 = 503 x 648 / 216

P2 =1509 kPa

ANSWERED AT 17/10/2019 - 09:06 AM


QUESTION POSTED AT 17/10/2019 - 09:06 AM

Two objects, Object A and Object B, need to be identified. Object A's index of refraction is determined to be 1.77, and Object B's index of refraction is determined to be 1.333. Knowing this information, which of the following must be true? A. Light can pass through Object B faster than it can pass through Object A. B. The optical density of Object A is lower than the optical density of Object B. C. The optical density of Object B is higher than the optical density of Object A. D. Light can pass through Object A faster than it can pass through Object B.

Answer: The correct answer is Option A.

Explanation: Optical density of a media determines the amount of light which  is slowed down when it is passes through a medium.

Refractive index is the measurement of optical density.

\text{Refractive Index}\propto \text{Optical density}

More the refractive index, more will be the optical density.

We are given that refractive index of Object A is 1.77 and refractive index of Object B is 1.333.

Optical density of Object A will be more than the optical density of Object B.

And light can pass easily through Object B because it is less dense than Object A.

Hence, the correct answer is option A.

ANSWERED AT 17/10/2019 - 09:01 AM


QUESTION POSTED AT 17/10/2019 - 09:01 AM

Tell how a voltaic cell works. be sure to mention the various parts of the voltaic cell and what they have to do with how it works

Voltaic cells are  used as a source of electrical power. By their nature, they produce direct current
A voltaic cell, or galvanic cell is an electrochemical cell that uses a chemical reaction to produce electrical energy. The cell consists of two metals: one called anode where oxidation (loss of electrons) occurs and the other cathode where reduction (gain of electrons) occurs.The salt bridge connect the anode with the cathode. It is the chamber of electrolytes necessary to complete the circuit in a voltaic cell.
The external circuit is used to conduct the flow of electrons between the electrodes of the voltaic cell and  includes a load.
The key to gathering the electron flow is to separate the oxidation and reduction half-reactions, connecting them by a wire, so that the electrons must flow through that wire.

ANSWERED AT 17/10/2019 - 08:33 AM


QUESTION POSTED AT 17/10/2019 - 08:33 AM

What happens as the activation energy increases? A. The pressure of the system decreases. B. The kinetic energy of colliding molecules changes. C. The reactant surface area decreases. D. The reaction begins to slow down.

When activation energy increases the kinetic energy of the colliding molecules changes.

Further Explanation

Collision theory  

  • According to collision theory for reactions to occur, molecules of reactants should effectively collide.
  • Effective Collision of molecules of reactants depends on their orientation which enables bond breaking and formation, together with the activation energy.

Activation energy  

  • Activation energy is the minimum or the least amount of energy required by the reactants for a chemical reaction to start. It is the energy needed to activate atoms or molecules of the reactants for a chemical reaction to occur.
  • Activation energy is also called the free energy of activation.  
  • Molecules or atoms of reactants collide with each other upon attaining the activation energy to form the products.

Effect of activation energy on rate of reaction

  • Activation energy varies inversely to the rate of chemical reaction such that an increase in activation energy results to a slower rate of chemical reaction.
  • Additionally, a decrease in activation energy results to an increased reaction rate. Higher activation energy results to lack of sufficient energy required for an effective collision.  

Keywords: Activation energy, collision theory

Learn more about:

Level: High school  

Subject: Chemistry  

Topic: Rates of reactions  

ANSWERED AT 17/10/2019 - 08:26 AM


QUESTION POSTED AT 17/10/2019 - 08:26 AM

How does photosynthesis works? step by step plz!

Chlorophyll absorbs the sun’s energy.

It is this energy that is used to split water molecules into hydrogen and oxygen.

Oxygen is released from the leaves into the atmosphere.

Hydrogen and carbon dioxide are used to form glucose or food for plants.

ANSWERED AT 17/10/2019 - 07:14 AM


QUESTION POSTED AT 17/10/2019 - 07:14 AM

Glass is different from a mineral because it ________. select one: a. does not have atoms arranged in an orderly pattern b. is not naturally occurring c. is not a solid d. contains carbon and is therefore organic

The correct answer is A. Glass does not have an orderly arrangement of the atoms, like the minerals. Glass lacks a crystal lattice structure, and is an amorphous solid. The atoms of glass are rigidly fixed but are arranged in an orderly fashion. 

ANSWERED AT 17/10/2019 - 06:17 AM


QUESTION POSTED AT 17/10/2019 - 06:17 AM

Which waves always require matter in order to propagate?a. Heat wavesb. Light wavesc. Sound wavesd. Transverse waves

I believe the correct answer is sound waves. It is the sound waves that always need matter or a medium in order to propagate. Sound waves are mechanical waves that has different characteristics to electromagnetic waves which does not requires a medium to travel. Mechanical waves depend on the particles interaction for it to travel hence a medium is needed.

ANSWERED AT 17/10/2019 - 05:14 AM


QUESTION POSTED AT 17/10/2019 - 05:14 AM

PLEASE HELP! How many grams of iron metal do you expect to be produced when 245 grams of an 80.5 percent by mass iron (II) nitrate solution react with excess aluminum metal? Show all work needed to solve this problem.

The mass of Fe(NO3)2 you have is 245 g * 0.805 = 197.23 g 

The molar mass of Fe(NO3)2 is 179.85 g/mole so you have 1.0966 moles 

From the balanced equation, that is the number of moles of Fe you make since both Fe(NO3)2 and Fe have a 3 in front of them. 

The mass of Fe is 1.0966 moles * 55.85 g/mole (atomic mass of iron) = 61.246 g. From the information you are given, your answer should be in 3 sig figs so 61.2 g 

Moles of HCl = 8.2 L * 3.5 mole/L = 28.7 moles 

From the balanced equation, you need 1/2 the moles of zinc as you have of HCl so you need 14.35 moles. 

To get the mass of zinc, multiply moles of zinc by its atomic mass = 938.2 g. From the information given, your answer should be in 2 sig figs so I would report it as 9.4 * 10^2 g, that clearly shows 2 sig figs.

ANSWERED AT 17/10/2019 - 04:56 AM


QUESTION POSTED AT 17/10/2019 - 04:56 AM

What happens to a glass of water as the average molecular kinetic energy of the water molecules increases? The water becomes more acidic. The water becomes warmer. The water becomes cooler. The water turns to ice.

Answer: The water becomes warmer.

Explanation:

Average kinetic energy is defined as the average of the kinetic energies of all the particles present in a system. The molecules start moving more randomly. It is determined by the equation:

K=\frac{3RT}{2}

From above, it is visible that kinetic energy is directly related to the temperature of the system. So, if the average molecular kinetic energy increases, the temperature of the water must have increased and thus the water will become warmer.

ANSWERED AT 17/10/2019 - 03:26 AM


QUESTION POSTED AT 17/10/2019 - 03:26 AM

Order these star structures from smallest to largest: cluster, Galaxy, local group, and supercluster

The answer is BCAD in smallest to largest

ANSWERED AT 17/10/2019 - 03:09 AM


QUESTION POSTED AT 17/10/2019 - 03:09 AM

Given below is a list of chemical reactions. 1. Burning octane fuel 2. Forming rust in an iron pipe 3. Baking a cake 4. Cement hardening Which sequence ranks the chemical reactions in order from fastest to slowest?

Answer is: 1, 3, 4, 2.

1) Burning octane fuel is very fast chemical reaction, it happens in immediately.

Main products of the combustion of fossil fuels are carbon(IV) oxide and water.

Chemical reaction: C₈H₁₈ + 25/2O₂ → 8CO₂ + 9H₂O; ΔH = -5500 kJ/mol.

2) Baking cake usually last for 30-60 minutes.

3) Cement hardening last for few days.

4) Forming rust usually last for few months.

Balanced chemical reaction of forming rust: 4Fe + 3O₂ → 2Fe₂O₃.


ANSWERED AT 17/10/2019 - 01:44 AM


QUESTION POSTED AT 17/10/2019 - 01:44 AM

What are two household appliances that use an electric motor? What does the motor make happen in each appliance.

An electric can opener and the fridgerator (google told me)

ANSWERED AT 17/10/2019 - 01:31 AM


QUESTION POSTED AT 17/10/2019 - 01:31 AM

Put hydrogen bonds dispersion forces and dipole-dipole forces in order

Increasing order of strength needed to break bonds:
temporary dipole induced dipole interactions
Permanent dipole induced dipole interactions
Hydrogen bonding

ANSWERED AT 17/10/2019 - 12:49 AM


QUESTION POSTED AT 17/10/2019 - 12:49 AM

Which of the following shows three elements in order of decreasing electronegativity? A)Br, Cl, F B) F, O, N C) Se, S, O D) C, N, O

Answer:

The correct answer is option D which is the decreasing order of conductivity is Mn, O, Ge.

Explanation:

You can easily answer this if you know the periodic trends. For the property of electrical conductivity, it decreases across a period and decreases also down a group. Thus, the most conductive element must be Mn, while the least conductive one is Ge. So, the answer is: -Mn, O, Ge

ANSWERED AT 17/10/2019 - 12:34 AM


QUESTION POSTED AT 17/10/2019 - 12:34 AM

What happens inside the object during blackbody radiation?

The light inside an object during a blackbody radiation would be continued to be absorbed as it hits the wall of the object.  A blackbody is referred to an object that absorbs all of the light that is pointed to it and does not reflect any. Hope this helps.

ANSWERED AT 17/10/2019 - 12:22 AM


QUESTION POSTED AT 17/10/2019 - 12:22 AM

3. In a first­ order reaction, what is the rate constant if the rate is 0.060M/s and the reactant concentration is 0.030M?

The rate law for a first order reaction is:
rate = k x [A]
where k is the rate constant and [A] is the concentration of the reactant A. The rate of a first order reaction depends only on concentration of one reactant.

Here, rate = 0.060 M/s and [A] = 0.030 M.
From the first equation, we can write:
k = rate / [A]
k = 0.060 M/s / 0.030 M = 2 s^-1

ANSWERED AT 16/10/2019 - 11:54 PM


QUESTION POSTED AT 16/10/2019 - 11:54 PM

What happens to the air temperature of a decending mass of air

When air descends it compresses. When the air compresses the molecules in the air knock into each other more often, increasing the tempertature.

Hope this helps

ANSWERED AT 16/10/2019 - 10:40 PM


QUESTION POSTED AT 16/10/2019 - 10:40 PM

Which statement regarding the second law of thermodynamics is true? A. Heat can transfer from a cold to a hot body without converting a certain amount of work to heat energy. B. Heat cannot transfer from a hot to a cold body without converting a certain amount of work to heat energy. C. Heat cannot transfer from a cold to a hot body without converting a certain amount of work to heat energy. D. Heat cannot transfer from a cold to a hot body without transferring mass first.

The Second Law of Thermodynamics says that processes that involve the transfer or conversion of heat energy are irreversible. ... The First Law of Thermodynamics states that energy cannot be created or destroyed; the total quantity of energy in the universe stays the same.

ANSWERED AT 16/10/2019 - 10:27 PM


QUESTION POSTED AT 16/10/2019 - 10:27 PM