Physics Flashcards
What is energy?
What are the Laws?
Energy is the ability to do work.
Laws of Energy:
1. Energy can cause CHANGES in a system
2. There are different FORMS of energy, with different PROPERTIES
3. These forms of energy can be TRANSFORMED
What is a system, and what are surroundings?
A SYSTEM can be defined as anything that is under observation. Everything around it is the SURROUNDINGS.
What is kinetic vs. potential energy?
Kinetic energy is the energy of motion. Anything moving has kinetic energy.
Potential energy is the stored energy an object has as a result of its condition and position.
It is possible for an object to have BOTH kinetic and potential energy at the same time.
What is the formula and unit for potential energy?
PE = m x g x h
Mass is in kilograms, Gravity is 9.8, Height is in meters
Unit: Joules
What is the formula and unit for kinetic energy?
KE = 1/2 x m x v^2
Mass is in kilograms, Velocity is in meters per second
Unit: Joules
What is the formula and unit for total energy or Etot?
Etot = PE + KE
Unit: Joules
What are some types of kinetic energy? List and give description
MTWS
Mechanical - The motion of objects larger than molecules
Thermal - How much particles are moving
Wind - The movement of turbines
Sound/Light - The waves move through space
What are some types of potential energy? List and give description
GEC
Gravitational - Gravity pulls objects towards centre of earth
Elastic - A stretched object wants to return to its original position
Chemical - Energy is stored in bonds
What is a law versus a theory?
Law - Proven in all situations
Theory - So far all evidence supports it, but we cannot prove its true
What is the first law of thermodynamics?
Energy cannot be created or destroyed
(It CAN change forms)
- When a system releases energy, the surroundings gain energy.
- When a system absorbs energy, the surroundings lose energy.
What is an open system vs closed vs isolated?
Open system - Heat energy AND particles can stay or leave
Closed system - Heat can get in and out, but particles CANNOT
Isolated system - NO heat and NO particles can go out
What is transforming vs transferring?
End of lesson 1
When energy is TRANSFERRED, it stays in the same form.
When energy is TRANSFORMED, the form of energy changes
What is mass?
A measure of the amount of matter in an object. (in kg)
What is velocity?
The speed of an object in a specific direction (in m/s)
Acceleration due to gravity
A fixed constant on earth at -9.8m/s^2 (9.8 m/s) assuming there is no friction to slow down a falling object.
Δ height / Change in height
Final position minus initial position
How to convert from kilojoules to joules?
1 Kilojoule = 1000 Joules, so;
Divide by 1000 to go from J to KJ
Multiply by 1000 to go from KJ to J
How to convert from kilometers to meters?
1 Kilometer = 1000 Meters, so;
Divide by 1000 to go from M to Km
Multiply by 1000 to go from Km to M
How do you calculate the neutrons for an atom?
What is atomic mass vs atomic number?
Why is the mass on the periodic table a non - integer (has decimals)?
Subtract atomic number by atomic mass to calculate the neutrons for an atom.
Total number of protons and neutrons is the atomic mass, atomic number is protons.
The number is the average
How to calculate weighted average?
(End of lesson 2)
Weighted average = (Mass of isotope 1) x (Abundance as decimal of isotope 1) + …
What is radioactivity?
How does it occur
- Radioactivity is the release of high-energy particles or waves.
- Radioactivity results from having an UNSTABLE nucleus.
- When these nuclei lose energy and break apart, FISSION occurs.
- Radioactive decay releases energy from the NUCLEUS as radiation.
Where can we find radiation?
- Radiation can exist naturally, and small amounts will not hurt us unless very frequent, but large amounts are bad
- Not all elements are radioactive, sometimes only certain isotopes of an element are radioactive
What happens in fission?
- The nucleus of an atom splits into two smaller nuclei
- This naturally happens to radioactive elements because the original element/nucleus was unstable, so it forms 2 more stable nuclei
What are the types of radiation?
Alpha radiation - The release of 2 neutrons and 2 protons
Beta radiation - The release of a single electron
Gamma radiation - The release of pure energy
