Physics Test (D1-D2) Flashcards
Kepler’s 1st Law is also known as?
The Law of Orbits
Kepler’s 2nd Law is also known as?
The law of Areas
Kepler’s 3rd Law is also known as?
The law of periods.
Kepler’s 1st Law
The planets orbit in elliptical paths, with the Sun at one of the two foci.
Kepler’s 2nd Law
- A line joining a planet and the Sun sweeps out equal areas in equal time.
- It expresses the fact that the speed of planets increases when moving toward the Sun and decreases moving away from the Sun.
Kepler’s 3rd Law
The square of a planet’s orbital period, T, is proportional to the cube of its average orbital radius, R.
𝑻^𝟐∝𝑹^𝟑
Newton’s Universal Law of Gravitation
𝑭=𝑮 (𝒎_𝟏 𝒎_𝟐)/𝒓^𝟐
F is in Newtons
The gravitational force is a fundamental attractive force that acts across space between masses.
Gravitational Field Strength
𝒈=𝑭/𝒎
Units N/kg or m/s^2
What happens when there are more than one gravitational field present at a point?
The field strength is equal to the sum of the fields.
What is the alternative equation for Gravitational Field Strength?
𝒈=−(∆𝑽_𝒈)/∆𝒓`
Gravitational Potential Energy
𝑬_𝒑=−𝑮 (𝒎_𝟏 𝒎_𝟐)/𝒓
Units: J
The work done when bringing a mass m from infinity to a point in space.
When is Gravitational Potential Energy zero?
When the distance of separation is infinite.
Is Gravitational Potential Energy of two bodies shared?
Yes
Gravitational Potential
𝑉_𝑔=−𝐺 𝑚_1/𝑟=𝐸_𝑝/𝑚_2
Units: J/kg
Gravitational Energy per unit mass.
Gravitational Potential Difference
Gravitational potential difference ∆𝑉_𝑔 is the work W, done per unit mass moved between two points within a gravitational field.
𝑾(J)=𝒎∆𝑽_𝒈
Escape Velocity
The minimum speed required to move out of a planet’s gravitational field.
𝑣_𝑒𝑠𝑐=√(2𝐺𝑀/𝑟)
Orbital Speed
The speed required for a satellite to be in circular orbit.
𝑣_𝑜𝑟𝑏𝑖𝑡𝑎𝑙=√(𝐺𝑀/𝑟)
How do you calculate the total energy of a satellite in circular orbit?
𝐸_𝑇=1/2 𝐸_𝑝=−𝐸_𝐾
(think total energy equals kinetic energy plus potential energy)
Field Lines
Vector arrows that show the direction of the field and are perpendicular to the surface of the mass.
What is the density/closeness of field lines proportional to?
Field Strength
Equipotential Surfaces
Lines that run parallel to the surface of the source of the field. The Gravitational Potential is equal at any point along an equipotential surface.
Laws of Conservation of Charge
Charge is conserved (objects coming into contact with each other transfers electrons)
Electric Charge (q)
𝒒=𝒏𝒆
𝒆=±𝟏.𝟔×〖𝟏𝟎〗^(−𝟏𝟗) 𝐂
Electrostatic induction
Exchanging of charges between two bodies without contact
Electric Field
The space that surrounds a charge or arrangement of charges.
Electric Field Strength
𝑬=𝑭/𝒒
Units: N/C
What is the alternative Electric Field Strength equation using potential difference V?
𝐸=𝑉/𝑑
Coulomb’s Law
Coulomb’s Law describes the electric force between two point charges.
𝑭_𝒆𝒍𝒆𝒄𝒕𝒓𝒊𝒄=𝒌 (𝒒_𝟏 𝒒_𝟐)/𝒓^𝟐
𝑘=1/(4𝜋𝜀_0 )
What is 𝜀_0?
𝜀_0 is the electrical permittivity of a vacuum (or air), it represents the ability of free space to transfer an electric force.
Millikan’s Experiment
Conducted in 1909 and confirmed that electric charge is a quantized quantity. Found the charge of electron or proton by varying voltage with oil drops suspended between two plates.
Electric Potential Energy
The work done when bringing all the charges of a system to their present position from infinity.
𝑬_𝒑=(𝒌𝒒_𝟏 𝒒_𝟐)/𝒓
Units: J
Electric Potential
The work done in moving a test charge from infinity to a point.
𝑽_𝒆=𝒌𝒒/𝒓
Units: J/C
𝑾=𝒒∆𝑽_𝒆
