physics year 9 eoy exam

Question 1

what is the equation for speed

Answer 1

speed = distance/time

Question 2

what is the equation for acceleration

Answer 2

acceleration = change in velocity/ time taken

Question 3

how do you determine acceleration from a velocity-time graph

Answer 3

gradient of the line (rise over run)

Question 4

how do you determine the distance travelled in a velocity time graph

Answer 4

area under the line

Question 5

what is a vector and what is a scalar

Answer 5

a vector is a measurement of both magnitude and distance, a scalar only has magnitude

Question 6

what is an insulator

Answer 6

current cannot flow through

Question 7

what is a conductor

Answer 7

current can flow through

Question 8

what is the equation for a force

Answer 8

f=ma

Question 9

what is the equation for weight

Answer 9

w=mg

Question 10

what forces would be acting on a block on a slope

Answer 10

normal reaction force upwards, gravitational force downwards, friction up the slope

Question 11

what forces would be acting on a ship moving to the right

Answer 11

gravitational force down, up thrust up
thrust to the right, air/water resistance

Question 12

what are some factors that could affect stopping distance (thinking and braking)

Answer 12

thinking:
- tiredness
- alcohol
- age
braking:
- bad tyre tread (no friction)
- bad breaks
- icy roads

Question 13

how is stopping distance calculated

Answer 13

thinking distance + braking distance

Question 14

how can you show that an object is charged?

Answer 14

it can pick up small bits of paper

Question 15

how can you show that there are different types if charges

Answer 15

• charge two pieces of the same plastic
• suspend on of the rods so it can swing freely
• hold the other rod still and they should repel
• then charge to rods of different plastic and repeat
• they should attract

Question 16

how would a rod and a cloth get charged

Answer 16

the cloth would transfer its electrons to the rod and becomes positive, the rod gains these electrons and becomes negative

Question 17

what is one potential danger of electrostatic charge?

Answer 17

sparks causing explosions

Question 18

what are the uses of electrostatic charges

Answer 18

• charged paint
  -photocopiers

Question 19

how is electrostatics used in photo copiers

Answer 19

• a rotating drum is given a positive charge
• a light is shined onto the paper to be copied and the reflection falls on the drum
  -the drum is made of a special material that conducts in light; positive charge leaks away
• negatively charged toner is spread on the drum
• the toner is only attracted to the charged area
• sheet of paper is passed over the drum
• the toner is transferred to the paper and heated to fuse it

Question 20

what is a longitudinal wave?

Answer 20

a longitudinal wave oscillates along the direction of travel

Question 21

what is a transverse wave?

Answer 21

a wave that oscillates perpendicular to the direction of travel

Question 22

what are two examples of longitudinal waves

Answer 22

• sound waves
• Seismic P waves

Question 23

what is the equation for wavespeed

Answer 23

wave-speed= frequency x wavelength

Question 24

what is the equation for frequency (using the time period)

Answer 24

frequency = 1/time period

Question 25

what are all the electromagnetic waves (in order of lowest frequency to highest)

Answer 25

non-ionising: - radio - micro - infrared - visible light ionising: - ultraviolet - x-ray - gamma

Question 26

what are the uses and danger of radio waves

Answer 26

broadcasting and communication no known dangers

Question 27

what are the uses and danger of micro waves

Answer 27

cooking and satellite transmission can cause burns, cataracts, or cancer

Question 28

what are the uses and danger of infrared

Answer 28

heaters and night vision skin burns

Question 29

what are the uses and danger of visible light

Answer 29

optical fibres and photography eye damage from bright lights

Question 30

what are the uses and danger of ultraviolet waves

Answer 30

discos, counterfeit detection, tanning salons skin cancer, damage to surface cells, blindness

Question 31

what are the uses and danger of x-rays

Answer 31

imaging internal structures of objects and materials, studying atomic structure damage to cells

Question 32

what are the uses and danger of gamma rays

Answer 32

cancer treatment, observing the universe, sterilising medical equipment cancer, cell mutation

Question 33

what is the human hearing range?

Answer 33

20-20,000hz

Question 33

what is the human hearing range?

Answer 33

20-20,000hz

Question 34

what is the definition of a wave front

Answer 34

Points on a wave that oscillate in phase with each other

Question 35

what are all the energy stores (8)

Answer 35

- thermal - electrostatic - kinetic - chemical - nuclear - elastic - gravitational - magnetic

Question 36

what are all the energy transfers

Answer 36

mechanical radiation electrical thermal/heating

Question 37

what is the principle of conservation of energy

Answer 37

energy cannot be created or destroyed, it can only be transferred input energy= output energy

Question 38

what is the equation for efficiency?

Answer 38

efficiency = useful energy output/energy input x100

Question 39

energy transfer for electrical energy

Answer 39

chemical store of fuel --> thermal store of water (heat) thermal store of water --> kinetic energy of turbines (mechanic) kinetic store of turbines --> kinetic store of electricity generator (mechanical) kinetic store of electricity generator --> electrical energy (electrically)

Question 40

equation for density

Answer 40

density = mass/ volume

Question 41

equation for pressure

Answer 41

pressure = force/ area

Question 42

equation for pressure difference

Answer 42

pressure = height x gravitational field x density

Question 43

properties of magnetically soft and magnetically hard materials + examples

Answer 43

soft: - easy to magnetise and demagnetise - iron hard - hard to magnetise and demagnetise - steel