1. A2 Physics Unit 4 Jan 2010 Multichoice A2 Physics Unit 4 Jan 2010 Multichoice Mr D Powell

2. Raw Marks.... A = B = C = D = E = U =

3. Mr Powell 2008 Index C Ft=mv-mu

4. Mr Powell 2008 Index B v = 2x10 -4 m 3 s -1 / 7.2x10 -4 m 2 = 0.2778ms -1 mass per second = 1000kgm -3 x 2x10 -4 m 3 s -1 = 0.2kgs -1 mv = 5.6 x 10 -2

5. Mr Powell 2008 Index D  Inelastic means that you lose some KE to thermal/sound in the smash  But you always conserve mass and total energy and momentum in any collision

6. Mr Powell 2008 Index A  =v/r = (6400 x10 3 x 2  / 24 x 60 2 )/ (6400 x 10 3 ) D FBI for C

7. Mr Powell 2008 Index B........

8. Mr Powell 2008 Index B Reason out what is happening to M on spring about a point. Time for cycle is down, up past zero to top and down to zero. i.e. 0.5s x 4 = 2s A is only halfway down

9. Mr Powell 2008 Index A Why? B – it is in phase C – It is the reverse! D – can happen in chemical or electrical systems as well

10. Mr Powell 2008 Index A Changes cancel out

11. Mr Powell 2008 Index D  Look at idea of velocity in circle v=r   Force on moving object in circle is F=mv 2 /r

12. Mr Powell 2008 Index B 1.Use formula for gravitation field on Earth. 2.Plug in new case then divide 2 by 1 to cancel all terms and give x 2 y 1 2

13. Mr Powell 2008 Index D Think of formula... The gravitational potential (V) is the potential energy (U) per unit mass:potential energy U = mV where m is the mass of the object. The potential energy is the negative of the work done by the gravitational field moving the body to its given position in space from infinity

14. Mr Powell 2008 Index A Think of new situation and plug in numbers

15. Mr Powell 2008 Index C 1.Work is only done then moving towards or away from electrode. 2.Equipotential means no PD between points 3.Hence no work against the field

16. Mr Powell 2008 Index B E-field is uniform D = ½ then V = ½ to cancel

17. Mr Powell 2008 Index C E=V/d Field is 1NC -1 Electric Potential is 1JC -1 V d

18. Mr Powell 2008 Index C 1.Energy = ½ mv 2 this is converted to potential energy V at point P 2.There is no way that total energy can be zero at this point or it would simply sit there and not reverse direction!

19. Mr Powell 2008 Index D........

20. Mr Powell 2008 Index B CV=Q Q=It CV=It CV/I =t

21. Mr Powell 2008 Index D  Look at equations Q = CV & E = ½CV 2 Q  V, E  C  Now put in values ratios are 1000: 100 in formula  Both come out as 10:1 X:Y

22. Mr Powell 2008 Index D F=BIL F = 0.2T x 8A x 0.4m F = 0.64N Electrons = 8 x 10 28 electrons/m 3 x (1x10 -6 m 2 x 8 x 0.4m) Force per electrons = 2 x 10 -23 N

23. Mr Powell 2008 Index C Same plane so no effect B r = mv / Bq r  m only correct one!

25. Mr Powell 2008 Index A Using formulae for induced e.m.f Rearrange to second line.... (mine complex version!)

26. Mr Powell 2008 Index A 1.Conducting Rod of length l moves through magnetic flux density (field strength per unit area) B at constant speed v.... 2.Distance travelled by rod is v∆t 3.Area of flux it cuts is lv∆t. 4.Magnetic flux =  = BA = B x lv∆t 5.Faraday law states e.m.f = ∆  / ∆t = Blv∆t/ ∆t = Blv 6.e.m.f = 1x10 -5 T x 60m x 150ms -1 = 0.09Tm 2 s -1 = 0.09 Vsm -2 m 2 s -1 = 0.09V