Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Fictitious force wikipedia , lookup
Electromagnetism wikipedia , lookup
Centrifugal force wikipedia , lookup
Electric dipole moment wikipedia , lookup
Lorentz force wikipedia , lookup
Neutron magnetic moment wikipedia , lookup
Magnetochemistry wikipedia , lookup
Weightlessness wikipedia , lookup
1. (a) Torque and moment are to do with ‘distance multiplied by force’ B1 (b) (i) moment = 6.0 × 0.40 moment = 2.4 (N m) B1 (ii) Weight / force acts through the pivot Or (perpendicular) distance from pivot is (reduced to) zero (wtte) Allow: weight is ‘vertically below’/‘directly below’ the pivot Reference to pivot / point P (wtte) is essential B1 [3] €v2. Any three from: 1. (Suspend plate from a point and then) mark a vertical line on the plate (wtte) 2. Plumb line / ‘pendulum’ (used to find the vertical line) 3. Hang from another point / place (and draw another vertical line) (wtte) 4. Where the lines intersect gives position of centre of gravity (wtte) Note: For 1st point accept ‘mark line of string’ Allow: 1 mark for ‘By trial and error find a position where the plate balances’ B1 × 3 [3] Ä`3. (sum of) clockwise moment(s) = (sum of ) anticlockwise moment(s) Not: ‘CWM = ACWM’ C1 (18 × 0.14) + (60 + 0.32) = 0.035F Allow: working in consistently in cm C1 F ≈ 620 (N) Note: Bald answer scores 3 marks Allow: 1 mark for 21.72 (N m) or 2172 (N cm) A1 [3] 4. (i) 1 3600 1.0 = X 2.5 Oakwood Park Grammar School C2 1 2 one mark for one correct moment, one mark for the second correct moment and equated to first moment A0 X = 1440 (N) C1 Y = 3600 – 1440 = 2160 (N) (ii) (iii) or 3600 1.5 = Y 2.5 A1 B1 Not a couple as forces are not equal B1 and not in opposite directions / the forces are in the same direction C1 P=F/A = 1440 / 2.3 10–2 = 62609 (6.3 104) B1 B1 unit Pa or N m–2 [9] 5. (i) 1 2. 3. (ii) The (distribution of the) mass of the lawn mower is not uniform B1 One correct moment about A stated B 110 or 350 20 B1 B = (350 20) / 110 (moments equated) B1 B = 63.6 (N) A0 A = 350 63.6 = 286(.4) (N) A1 A goes down and B goes up B1 Turning effect of B is less / B needs greater force to produce the same moment / if distance goes down force needs to go up (to maintain the same turning effect) B1 [6] 6. (i) pressure = force / area B1 (ii) moment = force multiplied by the perpendicular distance (from the line of action of the force) to the pivot B1 [2] Oakwood Park Grammar School 2 7. (i) FB 1.7 = 80 0.85 650 1.3 One moment correct allow 1 Analysis leading to 537 N F = 540 (ii) B2 i.e. FB = 913 / 1.7 (537) (N) A0 FA = 650 80 540 or F 1.7 = 650 0.4 80 0.85 = 190 (N) B1 (193 N) (iii) FA goes up FB goes down To obtain the same moment a smaller force is required if the distance from the pivot increases / (FA FB) is a constant / weight (of painter) transfers from support B to support A C1 A1 B1 B1 B1 [8] ÜÌ Oakwood Park Grammar School 3