Physics Test (D1-D2)

Question 1

Kepler’s 1st Law is also known as?

Answer 1

The Law of Orbits

Question 2

Kepler’s 2nd Law is also known as?

Answer 2

The law of Areas

Question 3

Kepler’s 3rd Law is also known as?

Answer 3

The law of periods.

Question 4

Kepler’s 1st Law

Answer 4

The planets orbit in elliptical paths, with the Sun at one of the two foci.

Question 5

Kepler’s 2nd Law

Answer 5

• 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.

Question 6

Kepler’s 3rd Law

Answer 6

The square of a planet’s orbital period, T, is proportional to the cube of its average orbital radius, R.
𝑻^𝟐∝𝑹^𝟑

Question 7

Newton’s Universal Law of Gravitation

Answer 7

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.

Question 8

Gravitational Field Strength

Answer 8

𝒈=𝑭/𝒎
Units N/kg or m/s^2

Question 9

What happens when there are more than one gravitational field present at a point?

Answer 9

The field strength is equal to the sum of the fields.

Question 10

What is the alternative equation for Gravitational Field Strength?

Answer 10

𝒈=−(∆𝑽_𝒈)/∆𝒓`

Question 11

Gravitational Potential Energy

Answer 11

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.

Question 12

When is Gravitational Potential Energy zero?

Answer 12

When the distance of separation is infinite.

Question 13

Is Gravitational Potential Energy of two bodies shared?

Answer 13

Yes

Question 14

Gravitational Potential

Answer 14

𝑉_𝑔=−𝐺 𝑚_1/𝑟=𝐸_𝑝/𝑚_2
Units: J/kg
Gravitational Energy per unit mass.

Question 15

Gravitational Potential Difference

Answer 15

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

Question 16

Escape Velocity

Answer 16

The minimum speed required to move out of a planet’s gravitational field.
𝑣_𝑒𝑠𝑐=√(2𝐺𝑀/𝑟)

Question 17

Orbital Speed

Answer 17

The speed required for a satellite to be in circular orbit.
𝑣_𝑜𝑟𝑏𝑖𝑡𝑎𝑙=√(𝐺𝑀/𝑟)

Question 18

How do you calculate the total energy of a satellite in circular orbit?

Answer 18

𝐸_𝑇=1/2 𝐸_𝑝=−𝐸_𝐾
(think total energy equals kinetic energy plus potential energy)

Question 19

Field Lines

Answer 19

Vector arrows that show the direction of the field and are perpendicular to the surface of the mass.

Question 20

What is the density/closeness of field lines proportional to?

Answer 20

Field Strength

Question 21

Equipotential Surfaces

Answer 21

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.

Question 22

Laws of Conservation of Charge

Answer 22

Charge is conserved (objects coming into contact with each other transfers electrons)

Question 23

Electric Charge (q)

Answer 23

𝒒=𝒏𝒆
𝒆=±𝟏.𝟔×〖𝟏𝟎〗^(−𝟏𝟗) 𝐂

Question 24

Electrostatic induction

Answer 24

Exchanging of charges between two bodies without contact

Question 25

Electric Field

Answer 25

The space that surrounds a charge or arrangement of charges.

Question 26

Electric Field Strength

Answer 26

𝑬=𝑭/𝒒
Units: N/C

Question 27

What is the alternative Electric Field Strength equation using potential difference V?

Answer 27

𝐸=𝑉/𝑑

Question 28

Coulomb’s Law

Answer 28

Coulomb’s Law describes the electric force between two point charges.
𝑭_𝒆𝒍𝒆𝒄𝒕𝒓𝒊𝒄=𝒌 (𝒒_𝟏 𝒒_𝟐)/𝒓^𝟐
𝑘=1/(4𝜋𝜀_0 )

Question 29

What is 𝜀_0?

Answer 29

𝜀_0 is the electrical permittivity of a vacuum (or air), it represents the ability of free space to transfer an electric force.

Question 30

Millikan’s Experiment

Answer 30

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.

Question 31

Electric Potential Energy

Answer 31

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

Question 32

Electric Potential

Answer 32

The work done in moving a test charge from infinity to a point.
𝑽_𝒆=𝒌𝒒/𝒓
Units: J/C
𝑾=𝒒∆𝑽_𝒆