2020 CAIE AS & A level October November Physics Paper 21 Q. No. 1 (9702/21/O/N/20) by Sajit C Shakya
2020 CAIE AS & A level October November Physics Paper 21 Q. No. 1 (9702/21/O/N/20) by Sajit Chandra Shakya from NEPAL Chapter: UNITS AND MEASUREMENT as well as FORCES (a) (i) Define the moment of a force about a point. (ii) Determine the SI base units of the moment of a force. (b) A uniform rigid rod of length 2.4m is shown in Fig. 1.1. The rod has a weight of 5.2N and is made of wood of density 790kgm–3. Calculate the cross-sectional area A, in mm2, of the rod. (c) A fishing rod AB, made from the rod in (b), is shown in Fig. 1.2. End A of the rod rests on the ground and a string is attached to the other end B. A support stick exerts a force perpendicular to the rod at point C. The weight of the rod acts at point D. The tension T in the string is in a direction perpendicular to the rod. The rod is in equilibrium and inclined at an angle of 56° to the vertical. The forces and the distances along the rod of points A, B, C and D are shown in Fig. 1.2. (i) Show that the component of the weight that is perpendicular to the rod is 4.3N. (ii) By taking moments about end A of the rod, calculate the tension T.
