Unit3 AOS1 - Application of Field Concepts

Question 1

Perception of Gravity

Answer 1

The human body doesn’t feel gravity, instead we feel normal forces - which give us a sense of gravity

In situations where there is no normal force, we may feel like there is no gravity - but it’s just a zero normal force

Question 2

What forces do satellites experience (and what is Fnet)

Answer 2

They will only experience the force due to gravity - which acts as a centripetal force - that points towards the center of the earth

Question 3

How many combinations of orbital period & speed exist for a single orbital radius

Answer 3

Only 1

For a given orbital radius - there will only be one orbital period & speed

Question 4

Satellite Orbit Velocity

Answer 4

Question 5

Satellite Orbital Period

Answer 5

Question 6

Effect of Satellite Mass on its Orbit

Answer 6

The Satellites mass has no impact on its radius, period and speed - only the mass of the orbiting body matters

Question 7

Where to measure Orbital Radius

Answer 7

From the CENTRE OF THE PLANET BEING ORBITED

(not the surface)

Question 8

Effect of Orbital Radius on GPE

Answer 8

Increasing Orbital Radius will increase GPE

Given that E(inital) = E(final), increasing orbital radius (which will decrease velocity & kinetic energy), must increase gravitational energy

Question 9

Geostationary Orbit

Answer 9

Occurs when the satellite will remain at the same location relative to the earths surface

Only occurs when:
the period of the orbit is equal to the period of the earth (one full day)
the satellite must orbit directly above the equator, and in the same direction as the earths rotation

Question 10

Magnitude of Magnetic Force on Current-Carrying Wires

Answer 10

Question 11

Direction of Magnetic Force on Current-Carrying Wires

Answer 11

Use the Right Hand Slap rule - with the thumb representing the direction of conventional current

Question 12

Conventional Current

Answer 12

Direction of flow of positive charge - from a positive to a negative terminal

Question 13

4x Components of a DC Motor

Answer 13

1. DC Voltage Source
2. Split Ring Commutator - to transmit the current in a way that allows continuous rotation
3. Coil of Wire - Used to allow the electrical current to flow through the magnetic field - creating the force
4. Magnetic field - required for the wire to move

Question 14

How to find the force on a DC Motor

Answer 14

Use F=nILB

Question 15

Split Ring Commutator

Answer 15

Changes the direction of current in the coil every half rotation, to produce a constant direction of torque on the coil

Question 16

How do Linear Particle Accelerators work?

Answer 16

They use an electric field between two planes to accelerate charged particles up to be very high speeds

This works by creating a voltage difference across the plates, then moving a charged particle into the field, upon which the charged particle will be propelled forwards

Question 17

Magnetic Particle Accelerators

Answer 17

A magnetic field can change the direction of a particle that has been linearly accelerated - this changes the direction of the particle (depending on if it’s positive or negative)