Hey guys, here is a started version of the mark scheme, credit to Uzair ALi and Carmen Chui.
lets get the rest of answers and also lets see which questions were how many marks
AQA AS Physics Paper 1 - Unofficial Mark SchemeNOTE: These are not entirely in order, and some answers may be inaccurate.
Question 1)a) In a jet engine, air enters at A and its velocity increases before leaving at B. What happens to its momentum?
The momentum increases as p = mv and the mass is constant but the velocity increases hence the momentum increases.
b) Why does air leaving the jet engine at B lead to an accelerating force on the aircraft.
Newton's 3rd law, equal force had an equal and opposite reaction force therefore it is thrusted forwards. Air moves out back, so plane moves opposite to direction of air. .
c) In one second, 210kg of air passes through the jet engine and the velocity of the air is increased by 570m/s. Work out the maximum accelerating force of the air on the jet engine.F = m x a or F = (mv)/t Force = 210 * 570 or Force = (210*570) / (1) Force = 119700 N (120000N 2s.f, or1.2x10^5)
d) When landing, the aircraft uses a deflector plate to use the air flowing through the jet engine to decelerate the aircraft. Does the momentum of the air change after the deflector plate is used?
The momentum of the air then changes because the air changes direction via the deflector plates.Momentum is a vector quantity with direction as a factor.
e) There is a decelerating force of 190kN on the aircraft which has a mass of 7x10^4Kg Work out the deceleration of the aircraft.190000 = 7x10^4 * aA = 2.714205A = -2.7m/s^2Deceleration is 2.7m/s^2f)
Assuming a constant decelerating force of 190kN, work out the distance taken for the aircraft to come to rest. The aircraft lands with a velocity of 68m/s.v^2 = u^2+2as0^2 = 68^2 + 2*-2.714205 (value of a from previous question)*sS = 851.78947s= 850m (2s.f.)
2)a) Suggest how a stationary wave can be formed in the microwave.
Microwave travels through the oven and reflects at the oven wall, superposition of 2 waves travelling in opposite directions with the same frequency creates a stationary wave. Same frequency/wavelength and same amplitude while travelling in opposite directions.
b) Wavelength = 11.8cm = 0.118mC=f(wavelength) f=c/(wavelength)=3x10^(8)/0.118=2.54x10^(9)m(If the measurement was 11.8cm. Mark scheme will probably allow 11.7 - 11.9cm)
c) Why do microwaves usually have a turntable?
Microwaves need a turntable to ensure food is heated evenly and not just at specific points of constructive interference.
(We should do the question about the long pipe probe and the diameter of the wire(P = RA/L)) length:0.5m
Calculate the total resistance of the circuitV=IR V=1.5, I=0.66 R=2.3 ohms
Define Tensile stress and strain
Stress = force applied per cross sectional area F/A
Strain = ratio of the extension to the original length (delta)L/LWhat property does
material A show?Brittle - breaks without deforming plastically
or Obeys ohms law, as force is proportional
Why are 2 protons produced in the annihilation of helium and anti helium nuclei?To conserve momentum and energy CalculSecond
Last question ) Anti Neutron -> Anti Proton + Positron(E+) + Electron neutrinod)
Which interaction is responsible for the above interaction? Weak interation