1 (a) (i) 22N
(ii) 11 J
(iii) conservation of energy is the idea that energy is never created or destroyed, only transferred or converted. It applies to Roy because his kinetic energy was converted into waste heat energy through conservation.
(b) 5.48 to 2dp - working below
35nx1.5m = 52.5j
G.D.P = energy transferred, so 53.5 = 1/2x3.5kgx(velocity)^2
Rearrange to get 30 = velocity ^2
Velocity = 5.48m/s
2 (a) (i) around 12.5 seconds
(ii) 6.5 m/s
(b) The top tick box, "speed increases, then decreases until the lorry becomes stationary"
(1 mark)(c) Reaction
(1 mark)(d) Because the forces are acting on different objects. The weight is acting on the road by the lorry and the reaction is acting on the lorry by the road.
3 Car crash seat belt and air bag
(6 marks)-in a collision, the car comes to a stop very suddenly
-change in momentum = resultant force x time for which the force acts, therefore as the change in momentum is constant and can't be changed, and as the time is very small, the resultant force is very large
-therefore passengers get injured because there is a large force acting on them, which causes a lot of pressure on the body in a short space of time.
-seat belts are slightly elastic so they stretch slightly. This means that, in a crash, the time taken for the body to stop moving is increased, so the force on the chest is reduced.
-air bags are released. Passengers' heads collide with these instead of the windscreen or dashboard, both of which are hard surfaces. As airbags are soft, they increase the amount of time taken for the passengers' heads to stop moving, so force to the head and neck is reduced.
-by reducing the amount of force, the pressure which the body undergoes is reduced, and so the risk and severity of injury are reduced significantly.
4 Explain how a transformer induces a voltage across the secondary coil: There is an alternating voltage on the primary coil which leads to an alternating current in the coil. This alternating current produces an alternating magnetic field in the iron core which induces an alternating voltage in the secondary coil.
(3 marks) 5 (a) Electromagnetic induction
(1 mark)(b) You could have said a few for this one: putting the opposite pole of the magnet in (ie south instead of north), spinning the magnet, taking the magnet out
(1 mark)(c) Because it increases the size of the voltage (and therefore current) in the wire.
(1 mark) 6 (a) Graph C (the one that looks like a sin graph)
(1 mark)(b) Iron
(1 mark)7 Resistance in parallel wires
(6 marks)-the results show a negative correlation, as the number of wires increases, the resistance in the wires decreases.
- increasing the number of pathways means the current gets shared, and therefore it is less in each wire
- this therefore reduces the resistance
- she could improve by using a wider range and more intervals to help get a clear trend
- she could use a different set of wires (possibly different length or width wires as both of these factors affect resistance)
8 If I remember rightly these were the calculation ones.
(a) (i) 5 Ω
(1 mark)(ii) 0.5 V
(1 mark)(b) (i) 1.5 V
(1 mark)(ii) 0.2 A
(1 mark)9 (a) Source C because:
- gamma radiation so it leaves the body quickly
- half life of around 1 hour so the exposure time is quite short and damage is limited
(3 marks)(b) Alpha radiation can't be detected by the badge because it is stopped by all 3 materials so can't pass through any of them.
(2 marks)(c) line drawn from beta to second box down
line drawn from gamma to top box
(2 marks - 1 mark for each line)(d) 4,500,000,000 J (or 4.5x10⁹ J)
(e) Eve, Ben
(2 marks, 1 for each correct)(f) He thinks that the perceived risk is higher than the statistical/calculated risk because he has no control over the plant, he doesn't know how it works and so might seem dangerous to him, past nuclear disasters, media and can't see radiation.
(3 marks)10 Irradiated vegetables
(6 marks)-irradiation means being exposed to ionising radiation without coming into direct contact with the source.
-irradiation is used on vegetables to sterilise them - ionising gamma radiation kills all the microbes on the food so it's safe to eat and has a long shelf life (no bacteria exist to grow as mould on it for a while)
-because irradiation doesn't involve contact with the source, the ionising effects stop as soon as the vegetables are removed from the source
-Donna's concerns are unfounded because the food is not radioactive, therefore she cannot become contaminated by eating the vegetables as she is not ingesting radiation
? Somewhere in the paper there was the question "how is high level radioactive waste dealt with?" But I don't know where it was: it is stored in glass and steel canisters in water for up to 50 years to cool, before being moved to more permanent storage (burial).
(2 marks)Feel free to add things, or change something you believe is wrong as I am in no way saying that my answers are definitely correct!
I thought I'd make a mark scheme because there have been an annoying lack of them for this board - and I know they're highly sought after. So enjoy!