M1. (a) (i) 4.5 allow 1 mark for correct substitution i.e

Size: px

Start display at page:

Download "M1. (a) (i) 4.5 allow 1 mark for correct substitution i.e. 9 2 2"

Daniella Haynes
8 years ago
Views:

1 M. (a) (i) 4.5 allow mark for correct substitution i.e. 9 (ii) m/s accept answer given in (a)(i) if not contradicted here (iii) (iv) speed straight line from the origin passing through (s, 9m/s) allow mark for straight line from the origin passing through to t = seconds allow mark for an attempt to draw a straight line from the origin passing through (,9) allow mark for a minimum of points plotted with no line provided if joined up would give correct answer. Points must include(0,0) and (,9) (b) (i) B if A or C given scores 0 marks in total smallest (impact) force on all/ every/ any surfaces these marks are awarded for comparative answers (ii) (conditions) can be repeated or difficult to measure forces with human athletes accept answers in terms of variations in human athletes e.g. athletes may have different weights area / size of feet may be different difficult to measure forces athletes run at different speeds accept any answer that states or implies that with humans the conditions needed to repeat tests may not be constant e.g. athletes unable to maintain constant speed during tests (or during repeat tests) do not accept the robots are more accurate removes human error is insufficient fair test is insufficient [0] Page of

9 (ii) m/s accept answer given in (a)(i) if not contradicted here (iii) (iv) speed straight line from the origin passing through (s, 9m/s) allow mark for straight line from the origin passing through

2 M. (a) (i) as one goes up so does the other or (directly) proportional accept change by the same ratio (ii) steeper straight line through the origin judge by eye (iii) Yes with reason eg data would have been checked / repeated accept produced by a reliable/ official/ government source do not accept it needs to be reliable or No with reason eg does not apply to all conditions / cars / drivers or are only average values or Maybe with a suitable reason eg cannot tell due to insufficient information (b) (i) stopping distance = thinking distance + braking distance (ii) any two from: factors must be to do with increasing braking distance smooth road / loose surface rain / snow / ice accept wet road/ petrol spills do not accept condition of road unless suitably qualified badly maintained brakes accept worn brakes accept bad/ worn/ rusty brakes do not accept old brakes worn tyres accept bald tyres accept lack of grip on tyres do not accept old tyres downhill slope/gradient heavily loaded car [6] Page of

are only average values or Maybe with a suitable reason eg cannot tell due to insufficient information (b) (i) stopping distance = thinking distance + braking distance (ii) any two from: factors must

3 M. (a) (i) accelerating accept getting faster accept speed / velocity increasing (ii) acceleration increases accept velocity / speed increases more rapidly do not accept velocity / speed increases (b) (i) acceleration = accept a = or a = do not accept velocity for change in velocity do not accept change in speed (ii) 5 do not accept a = allow mark for an answer of 900 or for correct use of 540 seconds (iii) velocity includes direction accept velocity is a vector (quantity) accept converse answer [6] M4. (a) (i) constant speed do not accept normal speed do not accept it is stopped / stationary in a straight line accept any appropriate reference to a direction constant velocity gains marks not accelerating gains marks terminal velocity alone gets mark (ii) goes down owtte accept motorbike (it) slows down Page of

seconds (iii) velocity includes direction accept velocity is a vector (quantity) accept converse answer [6] M4.

4 (b) (i) 0 (m/s) ignore incorrect units (ii) acceleration = do not accept velocity for change in velocity accept change in speed accept or or a = do not accept (iii) 4 or their (b)(i) 5 allow mark for correct substitution m/s m/s/s or ms or metres per second squared or metres per second per second (c) vehicle may skid / slide loss of control / brakes lock / wheels lock accept greater stopping distance or difficult to stop due to reduced friction (between tyre(s) and road) accept due to less grip do not accept no friction Page 4 of

squared or metres per second per second (c) vehicle may skid / slide loss of control / brakes lock / wheels lock accept greater

5 (d) any three from: do not accept night time / poor vision increased speed reduced braking force slower (driver) reactions NB specific answers may each gain credit eg tiredness (), drinking alcohol (), using drugs (), driver distracted () etc poor vehicle maintenance specific examples may each gain credit eg worn brakes or worn tyres etc increased mass / weight of vehicle accept large mass / weight of vehicle poor road surface more streamlined if candidates give three answers that affect stopping distance but not specific to increase award mark only [] M5. (a) mass (b) work (done) = force (applied) distance (moved in the direction of the force) do not accept correctly substituted figures for this equation mark accept W = Fs or W = Fd or W = Fh (well done) = force height_) mark formula independently allow = = J / joules KJ / kilojoules allow = for mark only no unit mark allow marks for correct answer if no working / correct working is shown Page 5 of

weight of vehicle poor road surface more streamlined if candidates give three answers that affect stopping distance but not specific to increase award mark only [] M5.

6 (c) Quality of written communication The answer to this question requires ideas in good English, in a sensible order with correct use of scientific terms. Quality of written communication should be considered in crediting points in the mark scheme Max.4 if ideas not well expressed A B not moving accept stationary or at rest B - C acceleration or C D acceleration accept increases speed / velocity accept gets faster comparison made that the acceleration B C is less than C D accept comparison made that the acceleration C-D is greater than B-C D E constant velocity E F deceleration accept steady speed or at 0.4 m/s accept decreases speed / velocity accept gets slower [0] Page 6 of

4 if ideas not well expressed A B not moving accept stationary or at rest B - C acceleration or C D acceleration accept increases speed / velocity accept gets faster

7 M6. (a) *evidence of acceleration = or gains mark but 0. gains marks units m/s for mark (b) (i) 000 or 960 for mark (ii) evidence of power = or weight speed (credit figures)/ (iii) gains mark but 00/76 or figure consistent with (b)(i) gains marks (c) evidence of force = mass acceleration or gains mark but 60 gains marks but 60 + weight of girder (060/00*) (or figure consistent with (b)(i)) gains marks [9] Page 7 of

(credit figures)/ (iii) gains mark but 00/76 or figure consistent with (b)(i) gains marks (c) evidence of

8 M7. (a) evidence of speed = (travelled) or or gains mark but or any correct calculation of gradient (except when zero) gains marks or gains mark units metres per second or m/s or ms - (not mps) for mark (b) evidence of calculating the two speeds ( and or 5 and ) (evidence of this may be in (a)) or noting distances travelled in same time (0 secs) i.e. 00m and 40m but.5 gains marks [5] M8. (a) 5 (m) allow mark for indicating the correct area allow mark for obtaining correct figures from the graph allow mark for calculating area of triangle (5) but omitting the rectangle underneath ( x 5) (b) allow mark for correct substitution into the correct equation ie / 00 [5] Page 8 of

secs) i.e. 00m and 40m but.5 gains marks [5] M8.

9 M9. (a) Quality of written communication for correct use of term speed in all correct examples Q Q describes all sections correctly for marks describes or section correctly for mark max A B constant speed do not accept pace for speed B C (has accelerated) to a higher (constant) speed C D goes back to original / lower (constant) speed allow for mark, initial and final (constant) speeds are the same accept velocity for speed ignore reference to direction (b) 6.5 allow answer to s.f. allow mark for drawing a correct triangle or for using two correct pairs of coordinates allow mark for correct use of y/x ignore units [6] M0. (a) idea that balanced by friction force* / pushing force equals friction force (*note balanced by unspecified force) or specification of relevant force but no reference to balancing in both (a) and (b) gains mark overall for mark (b) balanced by upwards force of table* for mark (c) makes it (slightly) warm / hot or wears it away (slightly) / damages surface for mark [] Page 9 of

same accept velocity for speed ignore reference to direction (b) 6.5 allow answer to s.f. allow mark for drawing a correct triangle or for using two correct pairs of coordinates allow mark for correct use of y/x ignore units [6] M0.

10 M. (a) there is a (maximum) forward force drag/friction/resistance (opposes motion) (not pressure) increases with speed till forward and backward forces equal so no net force/acceleration any 4 for mark each 4 (b) (i) F = ma = 50a a = 8 m/s for mark each 4 (ii) ke = / mv ke = / ke = J for mark each 4 (iii) W = Fd W = W = J for mark each 4 [6] M. (a) 7.5 correct answer with no working = if incorrect allow mark for (change in velocity from graph =) 5 mark for marks for N.B. correct answer from the incorrectly recalled relationship = marks Page 0 of

48 ke = 440 000 J for mark each 4 (iii) W = Fd W = 0 000.44 W = 440 000 J for mark each 4 [6] M. (a) 7.

11 (b) (4 5 seconds) the bungee jumper slows down (decelerates) (the rubber cord) stops the fall (5 6 seconds) the bungee jumper starts moving (accelerating) upwards (in the opposite direction) max marks if no correct indication of time [6] Page of

jumper starts moving (accelerating) upwards (in the opposite

12 Page of

Speed, velocity and acceleration

Chapter Speed, velocity and acceleration Figure.1 What determines the maximum height that a pole-vaulter can reach? 1 In this chapter we look at moving bodies, how their speeds can be measured and how