2022 VS Phy Prelims P3 Ans

Prelim 2022 P3 Qn Marks 1 (a) MMO Metre rule clamped in stand and aligned vertically with bench using a set- square and Reading taken when mass hanger A is not moving or Repeated readings taken to obtain average height 2 (b) MMO 2.76+2.75+2.82+2.50 4 = 2.71 𝑠 1 (c) MMO MA =60 g 1 (d) PDO 𝑃 = 0.060 ×10 ×1.0 2.71 = 0.221 J/s 1 (e) PDO t1 = 1.40+1.38+1.26+1.42 4 = 1.37 s P1 = 0.070 ×10 ×1.0 1.37 = 0.511 J/s 1 (f) P • the quantities that you should keep constant, ✓ the height h that mass hanger A falls through ✓ mass of mass hanger B ✓ the same type of string across the pulley ✓ the same pulley 1 • a detailed description of how you will perform the experiment, a. Set up the apparatus as shown in Fig. 1.1. b. Adjust the position of the clamp so that the height h = 1.000 m for mass hanger A and mass hanger B is at rest on the floor. c. Carefully place a 10 g slotted mass on mass hanger A and hold this mass hanger in position. d. Release the mass hanger A and start the stop watch. e. Measure and record the mass of mass hanger A, mass hanger B and the average time taken for mass hanger A to fall to the floor in a table. f. Repeat steps (b) to (e) for 5 more sets of readings of average time taken for additional mass added to the mass hanger A. g. Calculate the 1 𝑡2 / s-2 using the values for the average time taken. 1

• a suitable table in which to display your measurements and calculated values (you do not need to enter any data into the table), MA / g MB / g 1/(MA – MB) / g-1 time taken to fall height h t2 / s-2 t1 / s t2 / s t = ( 𝒕𝟏+ 𝒕𝟐) 𝟐 ) / s 1 • a statement of the graph that you would plot to test the relationship, Plot a graph of t2 / s-2 against 1/(MA – MB) / g-1 If the relationship is valid, 1/(MA – MB) will be linearly related to t2 with a positive gradient. 1 • a sketch of the graph that you would obtain if the suggested relationship is correct, 1 • an explanation of how you would obtain a value of the constant k from your graph. Constant k is the gradient of the graph plotted. 1 2 (a) MMO 𝒇 = 𝟏𝟎.𝟎+𝟏𝟎.𝟎 𝟐 f = 10.0 cm 1 t2 / s2 1 (𝑀𝐴− 𝑀𝐵) / g-1

(b) MMO x = 15.0 cm y = 30.0 cm 1 1 (c) MMO 𝑓 = (𝟏𝟓)(𝟑𝟎) 𝟏𝟓+𝟑𝟎 = 10.0 cm (9.0 to 11.0 cm) 1 1 (d) ACE ✓ The lens should be placed upright and parallel to the screen. This can be checked with a set square. ✓ Object must be directed at the centre of the lens ✓ The torchlight (the source), the lens and the screen must lie along a straight line. ✓ Avoid parallax error in reading from ruler scale by looking at right angle to it. 1 (e) ACE The image size becomes smaller and equal to object size, the image distance becomes nearer and equal to object distance. 1 1 3(a) V0 = 1.50 V