ACJC_H1_PHY_P2_MS

Qn 1(a) Systematic errors are errors in measurements whereby the errors have a fixed magnitude and sign or (Systematic errors are errors in measurements whereby the measurements deviate from the true value by a fixed magnitude and in the same direction.) Random errors are errors in measurements whereby the errors have varying magnitude and sign or (Random errors are errors in measurements whereby the measurements deviate from the true value by a fixed magnitude and a direction that is not fixed.) (b) g = 9.869 m s-2  ∆𝑔 𝑔 =  ( ∆𝑙 𝑙 + 2∆𝑡 𝑡 ) (or ( ∆𝑙 𝑙 + 2∆𝑇 𝑇 )) = (0.1% + 2%)  g = 0.21 g = 9.9  0.2 m s-2 2 (a) Total initial momentum of system = total final momentum of a system provided there is no net external force acting on the system. (b) Apply COM, 0.02(500) + 0 = (40 + 0.02) v v = 0.24988 m s-1 Apply COE, KE lost by block and bullet = GPE gained by block and bullet ½ mv2 = mgh ½ (0.24988)2 = 9.81 h h = 3.18 x 10-3 m Assumption: All KE converted to GPE / Air resistance is negligible 3 (a) Sum of forces zero in all directions Sum of torque / moments zero about any axes / point (b)(i) Taking moments about line of action of R, Clockwise M = Anti-clockwise M Tsin70° (0.07) + W / 7 (0.03) = W (0.11) T = 1.60713 W Resolving forces in the x-direction, RX = 1.60713 W cos70° = 0.54967 W Resolving forces in the y-direction, RY = W + 1.60713 W sin70° - W / 7 = 2.36735 W

R = √(0.54967 W)2 + (2.36735 W)2 = 2.43033 W (b)(ii) When taking moments about line of action of R to determine T, the moment due to the upward force on the foot is greatly reduced as both the upward force on the foot (due to the cane) and perpendicular distance from the foot to R is reduced, leading to a smaller T (and horizontal component of R) The reduced upper force on the foot (due to the cane) and smaller T also reduced the vertical component of R. Therefore R is reduced. 4a Bulb in 1 can be fully dark ( or totally switched off) In 2, there is always pd across bulb/ there is always current through bulb ( or equivalent) b Diagram with a switch in series with resistor Discuss the position of switch ci 𝑅 = 𝑉2 𝑃 = 2402 60 = 960 Ω ii Room temperature lower than working temperature Lower lattice vibration; Resistance lower 5 (a) Minimum freq of em radiation/photon for release of electrons from surface of metal (b) EMAX corresponds to electron emitted from surface electron (below surface) requires energy to bring it to surface, so less than EMAX (c)(i) = hc/ = 6.63 x 10-34 x 3.00 x 108 x 1.85 x 106 = 3.68 x 10-19 J (ii) 1/= 2.5 x 106, Emax = 1.3 x 10-19 J  = h/p = 2 h mE = 1.36 x 10-9 m 6 (a) Speed (km / h) Stopping distance (m) Thinking distance (m) Braking distance (m) 30 12.0 5.6 6.4 40 18.0 7.5 10.5 50 25.0 9.5 15.5 60 33.0 11.3 21.7 80 52.0 15.0 37.0 100 70.0 18.8 51.2 120 102.0 22.5 79.5 (b)(i) t =