2024 FHSS P2 PRELIM MS

Section A 1 (a) F = ma 145000 – 40000 = 60000a a = 105000 / 60000 = 1.75 m / s2 [1] [1] (b) a = (v – u) / t t = (v – u) / a = (60 – 0) / 1.75 = 34.3 s or 34 s [1] [1] (c) distance = ½ x 34.3 x 60 = 1030 m [1] [1] (d) Air resistance increases as the speed of the aircraft increases. Thus, the total resistive forces acting against the aircraft will increase with its speed. [1] 2 (a) W = mg = 60 × 10 = 600 N [1] [1] (b) When he pushes the floor, his body rises and moves through a distance in the same direction as the force F, hence work is done. [1] (c) Moment due to the weight about his toe = 600 N x 0.80 m = 480 Nm [1] [1] (d) By Principle of Moments, taking moments about his toes, F x 1.15 m = 480 F = 417 N or 420 N total upward force = total downward force F + R = W 417 + R = 480 R = 63 N or 60 N [1] [1] [1] (e) The force exerted by the hand on the floor. [1] 3 (a) F = pressure x area F = 1.2 x 106 x 5.0 x10–5 = 60 N [1] [1]

(b) Pressure in oil remains the same. (F1/A1 = F2/A2) There is a greater cross-sectional area at the brake pads. Thus a larger force will be applied. [1] [1] (c) Bubbles of air are highly compressible. Hence, some pressure is used to compress the bubbles and the pressure is not fully transferred to S. [1] [1] 4 (a) Air molecules are moving around randomly and at high speeds. They collide or hit the walls of the cylinder thus exerting a force on walls, resulting in pressure. [1] [1] (b) Molecules are now closer / spaced more compactly / more molecules per unit volume / less space to move. They collide more frequently with the wall of chamber, causing higher pressure [1] [1] 5 (a) Unlike charges attract. The negative charges on the teeth are attracted to the positively charges on the plaque. [1] (b)(i) When the hand is holding to the positively charged handle, the excess electrons on the tooth are attracted to the handle and neutralised. More electrons continue to be transferred to the handle due to the high positive charge. Since the teeth have more positive charges than negative charges, the teeth become positively charged. [1] [1] (ii) As opposite charges attract, the positively charged plaque is attracted to the negatively charged bristles of the toothbrush OR it is repelled by the positively charged teeth since like charges repel. [1] [1] [1] [1] (c) Q = It = 0.00015 x 5 x 60 = 0.045 C [1] [1] 6 (a)(i) A [1] [1] (ii) V [1] [1] b When brightness decreases, the resistance of LDR increases.

Since total resistance increases, the current flowing through the series circuit decreases. Since V = RI, potential diffe