DLISC1 - week 10

Question 1

what is physics

Answer 1

it is the study of various physical phenomena nad the fundemental laws governing it

Question 2

basic things of nature

Answer 2

force
motion
matter
light
sound
heat
electricity
magnetism

Question 3

what are the three types of natural phenomena

Answer 3

Physical: formation of rainbow, formation of clouds
Chemical: conversion of wood into ash, rusting of iron
Biological: pumping of blood by heart, exchange of gases through lungs

Question 4

what is classical physics

Answer 4

developed before 19th century
includes
classical mechanics
wave mechanics
thermodynamics
electromagnetism
optics

Question 5

what is modern physics

Answer 5

developed after 19th century
includes
atomic physics
nuclear physics
quantim mechanics

Question 6

what occupations use physics?

Answer 6

biologists
chemists
astronomers
civil engineers
mechanical engineers
electrical engineers
electronic engineers

Question 7

what are basic quantities?

Answer 7

physical quantity that cannot be defined in any other physical quantity.
- length
- mass
- time
- temperature
- electric current

Question 8

what are derived quantities? (ants)

Answer 8

physical quantities which are obtained fomr the base quantites using time or divide
- area
- volume
- speed
- force

Ants Vacationing Seek Fun

Question 9

what are scalars (Monkeys)

Answer 9

is a physical quantity that is completely described by its magnitude
- mass
- length
- speed
- distance
- power
- time

Monkeys Love Salsa, Dancing Past Turtles.

Question 10

what are vectors?

Answer 10

an object that has a magnitude and a direction
- displacement
- velocity
- acceleration
- friction

Question 11

what are Newtons 3 lawys of motion

Answer 11

1. An object in motion tends to stay in motion and an object at rest tends to stay at rest unless acted upon by an unbalanced force. (law of inertia)
2. Force equals mass times acceleration (F = ma)
   acceleration = a measurement of how quickly an object is changing speed
3. For every action there is an equal and opposite reaction. (action-reaction)

Question 12

what is it meant by an unbalanced and balanced force?

Answer 12

If the forces on an object are equal and opposite, they are said to be balances, and an object experiences no change in motion.

If they are not equal and opposite, then the forces are unbalanced and the motion of the object changes.

Question 13

what is electricity

Answer 13

the movement of electrons between atoms

Question 14

what is static electricity

Answer 14

The build-up of an electric charge on the surface of an object
The charge builds up but does not flow
Static electricity is potential energy. It does not move. It is stored

Question 15

what is static discharge?

Answer 15

Occurs when there is a loss of static electricity due to three possible things:
- Friction: rubbing
- Conduction: direct contact
- Induction: through an electrical field, not direct contact

Question 16

what are electricity currents

Answer 16

The flow of electrons from one place to another
Measured in amperes

Question 17

how can we control currents?

Answer 17

by electricity circuits
circuit: is a path of the flow of electrons
we use wires

Question 18

2 types of currents

Answer 18

Direct current (DC) – where electrons flow in the same direction in a wire
Alternating current (AC) – electrons flow in different directions in a wire

Question 19

2 types of circuits

Answer 19

Series circuit: the components are lined up along one path. If the circuit is broken, all components turn off
Parallel circuit: there are several branching paths to the components. If the circuit is broken at any one branch, only the components on that branch will turn off.

Question 20

what are conductors and insulators?

Answer 20

conductors: material thorugh which electric current flows easily
- metal
- water
insulators: materials which electric current cannot move
- rubber
- plastic
- paper

Question 21

what is resistance?

Answer 21

The opposition to the flow of an electric current, producing heat.
The greater the resistance, the less current gets through.
Good conductors have low resistance.
Measured in ohms.

Question 22

what infleunces resistance?

Answer 22

Material of wire – aluminium and copper have low resistance
Thickness – the thicker the wire the lower the resistance
Length – shorter wire has lower resistance
Temperature – lower temperature has lower resistance

Question 23

what is voltage?

Answer 23

The measure of energy given to the charge flowing in a circuit
The greater the voltage, the greater the force or “pressure” that drives the charge through the circuit

Question 24

what is Ohm’s law?

Answer 24

ohms law defines the correlation between electric current (I), voltage (V) and resistance (R) in a conductor.
can be expressed as V x I x R
- resistacne = voltage/current
- ohms = volts/amps

Question 25

what are the three primary electrical parameters?

Answer 25

1. the volt - the pressure that is put on free electrons that causes them to flow 2. the ampere - defines the flow of electric current 3. the ohm - the unit of resistance in a conductor - determined by: size, material and temperature

Question 26

magnets have two poles, what are they

Answer 26

norht pole south pole

Question 27

magnetic poles always exist between magnets

Answer 27

1. Like poles repel (south-south, or north-north) 2. Opposite oles attract (south-north)

Question 28

magnetic poles always occur in pairs

Answer 28

1. Magnetics poles can never be isolate 2. If you break a magnet, each piece will have a north and a south pole

Question 29

what are magnetic fields

Answer 29

A region in which a magnetic force can be detected. Direction of a magnetic field is the direction in which the north pole of a compass needle points at that location.