Answer for the quiz

  

 I.

1.  A type of energy that cannot be created or destroyed?
   Answer: Heat
2. States that the volume of a gas varies inversely with the pressure?
   Answer: Boyle's Law
3. The most common practical use of the first law of thermodynamics?
   Answer: Heat engine
4. The energy transferred from the object is?
   Answer: Negative work
5. When the object is stationary, its kinetic energy is?
   Answer: Zero

  II. 

1. Being in the wrong place when an African elephant—mass = 6000 kg, velocity = 10 m/s—is charging can really ruin your day. How fast would a 10 kg cannonball travel if it had the same kinetic energy as the elephant?
   
   Solution
   
2. A 30.0 L sample of nitrogen inside a rigid, metal container at 20.0 °C is placed inside an oven whose temperature is 50.0 °C. The pressure inside the container at 20.0 °C was at 3.00 atm. What is the pressure of the nitrogen after its temperature is increased to 50.0 °C?
   
   Solution
   
3. A gas has a volume of 800.0 mL at −23.0 °C and 300.0 torr. What would the volume of the gas be at 227.0 °C and 600.0 torr of pressure?
   
   Solution
   
4. If the spring is displaced for 75 cm and the work done to move the spring is --3.3 Joules, Find the spring force
   
   Solution
   
   
   
   
5. A Technician lifted a 1-kg power supply off the ground and it takes 5 seconds to move the power supply from the ground  to the table that has a height of 1.2 meter

       Solution
        the initial position of the power supply is from the ground

          so our initial height is Zero

         

         

QUIZ

   I. Identify the following

1.  A type of energy that cannot be created or destroyed?
2. States that the volume of a gas varies inversely with the pressure?
3. The most common practical use of the first law of thermodynamics?
4. The energy transferred from the object is?
5. When the object is stationary, its kinetic energy is?

  II.Solve the following 

1. Being in the wrong place when an African elephant—mass = 6000 kg, velocity = 10 m/s—is charging can really ruin your day. How fast would a 10 kg cannonball travel if it had the same kinetic energy as the elephant?
2. A 30.0 L sample of nitrogen inside a rigid, metal container at 20.0 °C is placed inside an oven whose temperature is 50.0 °C. The pressure inside the container at 20.0 °C was at 3.00 atm. What is the pressure of the nitrogen after its temperature is increased to 50.0 °C?
3. A gas has a volume of 800.0 mL at −23.0 °C and 300.0 torr. What would the volume of the gas be at 227.0 °C and 600.0 torr of pressure?
4. If the spring is displaced for 75 cm and the work done to move the spring is --3.3 Joules, Find the spring force  
5. A Technician lifted a 1-kg power supply off the ground and it takes 5 seconds to move the power supply from the ground  to the table

all of the given problems have a solution that i also properly explained at the bottom of the page

     


































































Answer for the quiz


refference
https://www.chemteam.info/GasLaw

First Law of Thermodynamics

The First Law of Thermodynamics states that heat is a form of energy, and thermodynamic processes are therefore subject to the principle of conservation of energy. This means that heat energy cannot be created or destroyed. It can, however, be transferred from one location to another and converted to and from other forms of energy. 

Internal energy

Application of the First Law

Heat engines 

The most common practical application of the First Law is the heat engine. Heat engines convert thermal energy and this heat energy is utilized converting it mechanical energy

Stirling engine
A Stirling engine is a heat engine that operates by cyclic compression and expansion of air or other gas (the working fluid) at different temperatures, such that there is a net conversion of heat energy to mechanical work.

Refrigerators and air conditioners 

 Air conditioners and Refrigerators don’t actually produce cold

The working principle of a refrigerator and air conditioner is very simple: it involves the removal of heat

 

Heat pumps

A heat pump is simply an air conditioner that is working in reverse.

When it's cold outside a heat pump extracts this outside heat and transfers it inside. When it's warm outside, it reverses directions and acts like an air conditioner, removing heat from your home. One advantage of a heat pump is that it moves heat instead of generating heat, giving you more energy efficiency.

We can also discuss the Second law of thermodynamics using this application

The second law of thermodynamics states that heat can only flow from hotter to something cooler

Air conditioner and heat pump follow the similar law of thermodynamics.

The heat pump absorbs heat from the atmosphere and supplies it to the room which is cooler in winters.

 The air conditioner removes heat from the room and maintains it at a lower temperature by throwing the absorbed heat into the atmosphere. 

reference
https://commons.wikimedia.org/wiki/File:Window_air_conditioner_working.gif
https://www.youtube.com/watch?v=EIP3pSio7-M
https://makeagif.com/gif/how-a-ground-source-heat-pump-works-hd-BdgU-L

Gas Law's

 Relationship of Pressure with Volume and Temperature

This video is a short explanation about the formulas of Gas law
Warning!!!Decrease your volume XD

Boyle's Law

for a given mass of gas at a constant temperature the volume of a gas varies inversely with the pressure

Example problem

A sample of gas occupies  7 L under a pressure of  2.2 atm. what would its volume be if the pressure were increased to 3.6 atm?*(assuming temp is constant)

Charle’s Law

at a constant pressure and for constant mass, the volume of a gas is directly proportional to the temperature.

Example problem

What is the final volume if a 20 L sample gas is heated from 25-degree Celsius to 50-degree Celsius?
(assuming pressure is constant)

Gay-Lussac’s law

Gay-Lussac accidentally discovered that at fixed volume and mass of a gas, the pressure of that gas is directly proportional to the temperature. This mathematically can be written as: p ∝ T

Example problem

The pressure in an automobile tire is 1.92 atm at 25-degree Celsius what will be the pressure if the temperature warms up to 37-degree Celsius?

Combined Gas law

The Combined gas law or General Gas Equation is obtained by combining Boyle's Law, Charles's law, and Gay-Lussac's Law. It shows the relationship between the pressure, volume, and temperature for a fixed mass (quantity) of gas:

Example problem

A  helium balloon has a volume of 3 L at 25-degree Celsius and 1.08 atm find the final pressure of the if its final volume is 4.2 L at 10-degree Celsius?

Avogadro's law

Equal Volume of gases at the same temperature and pressure contains equal number of particles.

Example problem

If a 0.36 mol of argon gas occupies a volume of 7.62 ml, what volume would a 0.33 mol of argon have if they have the same temperature and pressure?
Given
argon                   argon
n=0.36 mol         n=0.33 mol
V=7.62 ml          V=?

I made this gif to explain that Avogadros law is the only Gas law that is not included to the 

Combined gas law formula

Reference

https://www.toppr.com/guides/chemistry/states-of-matter/gas-laws/

https://en.wikipedia.org/wiki/Gas_laws#Combined_and_ideal_gas_laws

Kinetic Energy and Work

What is kinetic energy?

Kinetic energy K is the energy associated with the state of motion of an object. The faster the object moves, the greater is its kinetic energy. When the object is stationary, its kinetic energy is zero but it will have potential energy.

The difference of kinetic energy and Potential Energy

kinetic energy is the energy that an object contains because of a particular motion. On the other hand, potential energy is the stored energy, because of its state of rest.

potential energy increases as weight and height increases

 Examples of Kinetic Energy:

An airplane has a large amount of kinetic energy in flight due to its large mass and fast velocity.

Kinetic energy is not a vector. So a tennis ball thrown to the right with a velocity of 5 m/s, has the exact same kinetic energy as a tennis ball thrown down with a velocity of 5 m/s.

How can we calculate kinetic energy?

 kinetic energy (KE) is equal to half of an object's mass (1/2*m) multiplied by the velocity squared.

Example problem

What is the Kinetic energy of 145 g baseball with a velocity of 42.5 m/s? 

Solution

This video is a short explanation of Kinetic energy

it also contains additional example problems about kinetic energy

Warning!!!Decrease your volume XD

*The initial velocity of Problem 2 is zero because the locomotives are parked or not moving* 

Work

Work "W" is energy transferred to or from an object  by means of force acting on the object

1.)The energy transferred to the object is positive work
2.)The energy transferred from the object is negative work

In Physics, work is the displacement of an object due to force.

Work done by  gravitational force 
Work done by  spring force
Work done by a variable force

These three topics include forces and displacement so they are considered as subtopics for work. I also included the topic of Power in terms of work

Work done by  a Gravitational force

We already know that

For the gravitational force, we consider the change of distance in terms of y-axis

So the equation should be

The gravity is always downward

So we can say that the work done by a gravitational force is negative in every opposing force

Example problem

A mechanic lifts a 40-kg engine off the ground at a constant speed of 3m/s.

after the engine is lifted 2 meters, calculate the work done by the gravitational force 

Solution

the initial position of the engine is from the ground

so our initial height is Zero

Work done by  spring force

where:

k=is the spring force

most of the spring force problems the initial value at 0 m

therefore, our equation will be

Example problem

find the work done of a spring having a spring force of 200 N/m if the spring is compressed 0.025 meter?  

Given

spring constant=200N/m

Distance=0.025

Work done by  variable force

Example problem

find the work done to lift a 20 kg from the floor to a height of 3 m when the variable force f(x) is given in newtons.

Given force

Solution

Power in terms of work

Power is the rate of doing work or using energy

Example problem

It takes 12000J of work to lift an elevator to the 3rd floor of a building ,if this is done in 8 seconds what is the rate of work?

Solution

it takes 1500 watts to lift the elevator to the 3rd floor

1730, space, start text, m, i, slash, h, r, end text, right parenthesis

referrence
https://www.khanacademy.org/science/ap-physics-1/ap-work-and-energy/kinetic-energy-ap/a/what-is-kinetic-energy