Physics

Question 1

What is terminal velocity

Answer 1

when the weight of the object falling and the air resistance is the same, therefore leaving us with no resultant force

Question 2

What is the SI unit of density

Answer 2

kg/m³

Question 3

What does density equal to

Answer 3

Density = mass/volume

Question 4

what is hooke’s law

Answer 4

a law stating that the strain in a solid is proportional to the applied stress within the elastic limit of that solid.

Question 5

What is the weight of a body of mass 1kg

Answer 5

the weight of a body of mass 1kg is 9.8N (often taken as 10N)

Question 6

What is the weight of a body

Answer 6

The weight of a body is the force of gravity on it

Question 7

Weight equation

Answer 7

weight equals mass X gravitational field strength

Question 8

How to determine resultant force on a suspended weight

Answer 8

Amount of Newtons (on cable) x sine(angle the cable makes with horizon)

Question 9

What does moment equal to

Answer 9

Force X distance

Question 10

How long can an object stay upright

Answer 10

until the centre of mass is outside the base

Question 11

the greater the distance from the hinge… (moment)

Answer 11

The less force required to move an object

Question 12

What is work

Answer 12

Work is force x distance moved in direction of force

Question 13

what are the two quantities to measure to calculate the useful work done when a load is lifted from the ground to a higher level

Answer 13

Weight and height

Question 14

Why is the force required to lift a load higher when it is just leaving the floor

Answer 14

there is a force needed to get it started

Question 15

What is the unit of work

Answer 15

Joules, the work done when 1 newton moves through 1 meter

Question 16

What is the Kinetic energy equation

Answer 16

which is 0.5mv^2

Question 17

Name three different emerge resources used to obtain energy directly from water

Answer 17

hydroelectric
tidal
wave

Question 18

How does wave energy convert to electrical energy

Answer 18

Wave power converts the periodic up-and-down movement of the oceans waves into electricity by placing equipment on the surface of the oceans that captures the energy produced by the wave movement and converts this mechanical energy into electrical power.

Question 19

what is gas pressure equal to

Answer 19

Atmospheric pressure + pressure due to liquid column

Question 20

resistance equation

Answer 20

Voltage(V)/resistance(A)

Question 21

How many Amps is one mA

Answer 21

1000

Question 22

What measures current

Answer 22

Ammeter

Question 23

what measures volts (pd)

Answer 23

Voltmeter

Question 24

how to calculate current

Answer 24

Current = voltage/resistance

Question 25

voltage equation

Answer 25

Current x resistance

Question 26

how do variable resistors work

Answer 26

A variable resistor works by adjusting the path that current has to flow. ... The dial you turn will move another piece of wire inside the resistor. The end result is that the electricity will travel through a certain length of the strip depending on where you turn the knob.

Question 27

what are the two types of resistor setups

Answer 27

Parallel, series

Question 28

How to calculate combined resistance in parallel

Answer 28

``` 1/R1 = 1/R1 + 1/R2 etc… 1/R1 = 3/R2 R1/1 = R2/3 ```

Question 29

When is a current induced in the wire (u shaped magnet)

Answer 29

A current is induced in the wire when it is moved up or down between the magnet poles

Question 30

What does the voltage increase with

Answer 30

the speed of motion of the magnet or coil The number of turns on the coil the strength of the magnet

Question 31

What is Faraday’s law

Answer 31

The size of the induced p.d. is directly proportional to the rate at which the conductor cuts magnetic field lines

Question 32

what is Lenz’s law

Answer 32

The direction of the induced current is such as to oppose the change causing it

Question 33

Right hand rule

Answer 33

thuMb: Motion First finger: Field seCond finger: induced Curret

Question 34

How does a simple a.c. generator (alternator) work

Answer 34

It consists of a rectangular coil between the poles of a C shaped magnet The ends of the coil are joined to two split rings on the axle and against which carbon brushes press. When the coil is rotated it cuts the field lines and a voltage is induced in it

Question 35

How does a simple d.c. generator (alternator) work

Answer 35

An a.c. generator becomes a direct current if the slip rings are replaced by a commutator like that in a d.c. motor The brushes are arranged so that as the coil goes through the vertical, changeover of contact occurs from on half of the split ring of the communicator to the other. But it is when the coil goes through the vertical position that the voltage induced in the coil reverses, so one brush is always positive and the other negative

Question 36

transformer equation

Answer 36

Secondary voltage/primary voltage = secondary turns/primary turns

Question 37

How is voltage increased/decreased across transmission lines

Answer 37

Step up/ step down transformers

Question 38

What is the purpose of the iron core

Answer 38

Magnetic linkage

Question 39

List five devices that make use of electromagnetic induction

Answer 39

transformer, generator, dynamo, microphone, alternator

Question 40

What is meant by electromagnetic induction

Answer 40

Magnetic field cut by conductor induces a current

Question 41

how to increase the magnitude of the induced emf in this experiment

Answer 41

Move magnet faster, stronger magnet, more turns of solenoid

Question 42

how to calculate mass of water

Answer 42

Mass = volume × density

Question 43

How to calculate work

Answer 43

Work = Force × Distance

Question 44

How to calculate density of liquid

Answer 44

divide mass by volume

Question 45

what increases the sensitivity of a thermometer

Answer 45

A capillary tube with a very small diameter

Question 46

define virtual image

Answer 46

an optical image formed from the apparent divergence of light rays from a point, as opposed to an image formed from their actual divergence.

Question 47

How is a virtual image made

Answer 47

Virtual images form when light rays from the same location on an object reflect off a mirror and diverge or spread apart. Real images form when light rays from the same location on an object reflect off a mirror and converge or come together.

Question 48

A student wants to demagnetise a steel bar. He switches on the circuit for a few seconds and then switches off. He finds that the steel bar is still magnetised. How should he improve his method

Answer 48

Remove the steel bar from the coil whilst the circuit is switched on

Question 49

REMINDER

Answer 49

Study logic gates and circuits, can’t do flash cards for it

Question 50

A beam of electrons is passed through the magnetic field of a magnet, how must the magnet be positioned to deflect the beam in the direction shown

Answer 50

Have the magnet on its side, with S on the top and N on the bottom, when the electrons go through it will be redirected