Required Recall (Courtesy of Jack)

Question 1

What are the 7 SI units and quantities?

Answer 1

Length - meter (m)
Time - second (s)
Amount of substance - mole (mole)
Electric current - ampere (A)
Temperature - kelvin (K)
Luminous intensity - candela (cd)
Mass - kilogram (kg)

Question 2

It is stated after the measurement as ±
For example 48 ± 0.5 kg, 21.4 ± 0.05s, 105.43 ± 0.01N, 6 ± 0.8J

How do we work out the absolute uncertainty?
A) When we do have a range of values
B) When we do not have a range of values

Answer 2

A) If we have a range of values the absolute uncertainty is half the range of values.
B) If we do not have a range of values the absolute uncertainty is half the resolution of the measuring instrument.

Question 3

_____ 10^12 1 000 000 000 000 trillion
_____ 10^9 1 000 000 000 billion
_____ 10^6 1 000 000 million
_____ 10^3 1 000 thousand

Answer 3

tera T 10^12 1 000 000 000 000 trillion
giga G 10^9 1 000 000 000 billion
mega M 10^6 1 000 000 million
kilo k 10^3 1 000 thousand

Question 4

_____ 10^-3 0.001 thousandth
_____ 10^-6 0.000 001 millionth
_____ 10^-9 0.000 000 001 billionth
_____ 10^-12 0.000 000 000 001 trillionth

Answer 4

milli m 10^-3 0.001 thousandth
micro u 10^-6 0.000 001 millionth
nano n 10^-9 0.000 000 001 billionth
pico p 10^-12 0.000 000 000 001 trillionth

Question 5

The formula for the area of a circle and volume of a sphere.

Answer 5

area of circle = πr^2

volume of sphere = 4/3 πr^3

Question 6

State the definitions for scalar and vector quantities and give examples of each

Answer 6

scalar = has a magnitude, temperature
vector = has direction and magnitude, Velocity

Question 7

Label the quantities shown by the slopes and areas of distance-time, velocity-time, and acceleration-time graphs

Answer 7

distance/time: slope shows speed and area shows total displacement.
velocity/time: slope shows acceleration and area shows total distance
acceleration/time: slope shows acceleration at that point and area shows the change in velocity

Question 8

if an object is thrown at 16ms at an angle of 40 to the horisontal, resolve for the horisontal and vertical components.

Answer 8

horisontal = 16cos(40) =12.26

vertical=16sin(40)=10.28

Question 9

State Newton’s Laws of motion

Answer 9

Newton’s first law states that an object will stay at constant velocity unless acted upon by an unbalanced force.
Newton’s second law, F=ma
Newton’s third law is that when a force is exerted on an object a directly opposite force thats equal in magnitude occurs on the object.

Question 10

State the properties of pairs of forces in an interaction between bodies

Answer 10

The size of the force on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object.

Question 11

State the principle of conservation of linear momentum

Answer 11

If no external forces act on two colliding objects, then the vector sum of the linear momentum of each body remains constant

Question 12

State the definition of ‘the moment of a force’

Answer 12

the moment of a force is the total sum of it’s clockwise and anti-clockwise rotational forces

Question 13

State the principle of conservation of energy

Answer 13

the total energy of an isolated system remains constant

Question 14

State the definition for current

Answer 14

charge per unit time (rate of flow of charge)

Question 15

Derive the equations for combining resistances in series

Answer 15

V1=IR1, V2=IR2
Vt=V1+V2+V3
Vt=IR1+IR2+IR3
V=I(Rt)
Rt=R1+R2+R3

Question 16

Derive the equations for combining resistances in parallel

Answer 16

Vt=V1=V2=V3
It=I1+12+I3
I1=V/R1, I2=V/R2,=I3=V/R3
I=V(1/R1+ 1/R2+1/R3)  
1/Rt = 1/R1+ 1/R2+1/R3

Question 17

State the definition of electromotive force (e.m.f.)

Answer 17

energy per unit electric charge that is imparted by an energy source

Question 18

decribe the structure of a metal

Answer 18

atoms arranged in a regular patterns with a sea of delocalised electrons

Question 19

describe laminar and turbulent flow

Answer 19

laminar flow = the flow of a liquid with streams parallel to eachother.
turbulent flow = the flow of liquid with streams that cross and go back on themself

Question 20

State the conditions in which Stoke’s Law applies

Answer 20

a smooth sphere moving through laminar flow with constant velocity and tempreture

Question 21

State the relationship between upthrust and displaced fluid

Answer 21

the upthrust on an object in a fluid is equal to the weight of the fluid displaced

Question 22

Define the term limit of proportionality

Answer 22

the force at which hooks law no longer applies

Question 23

Define the term elastic limit

Answer 23

the point at which additional force will permanently disfigure a material

Question 24

Define the term yield point

Answer 24

the stress beyond which a material deforms plastically

Question 25

What is the difference between elastic and plastic deformation

Answer 25

Elastic deformation is when the material will return to its original shape.
Plastic deformation is when the deformation is irreversible

Question 26

the quantities shown by the slopes and areas of a force-extension graph

Answer 26

Slope = spring constant

Area = work done

Question 27

the definitions of transverse and longitudinal waves

Answer 27

transverse = the waves movement perpendicular to its propogation
longditudional =the movement of the wave is parallel to its propogation

Question 28

State the definition of amplitude

Answer 28

the maximum displacement of an oscillation

Question 29

State the definition of wavefront

Answer 29

when all the points on a wave have the same phase

Question 30

State the definition of coherence

Answer 30

waves are coherent if they are constantly in phase

Question 31

State the definition of path difference

Answer 31

the difference in the distance between two waves.
nλ = in phase,
(n+0.5)λ = out of phase

Question 32

State the definition of superposition

Answer 32

the resultant displacement at the point multiple waves meet

Question 33

State the definition of interference

Answer 33

when multiple waves of the same frequency cross and combine their vector displacement

Question 34

State the definition of phase

Answer 34

a specific point on a wave in relation to that same point on the same type of wave

Question 35

definition standing wave

Answer 35

when a waves profile doesn’t move and only oscilates up and down

Question 36

difference between a node and anti-node

Answer 36

a node has zero amplitude while the anti-nodes have the maximum amplitude.

Question 37

difference between real and virtual image

Answer 37

A real image iswhen the rays of light meet at a point whereas a virtual image is formed when the rays of light meet at a point in the ‘minds eye’

Question 38

State the definition of plane polarisation and give examples of its use

Answer 38

When only one frequency of wave is allowed through a screen. This can be used to block uv rays in sunglasses by only allowing visible light.

Question 39

definition of diffratcion

Answer 39

Diffraction is when waves spread out a as they pass through a gap or move around an object

Question 40

Describe diffraction experiments that provide evidence for the wave nature of electrons

Answer 40

single electrons were fired through a diffraction grating and onto a detector. The pattern on the detector showed interference which cant be explained with partical physics.

Question 41

The formula for the area of a trapezium.

Answer 41

area of a trapisium= (a+b)/2 *h