Page 267 - Physics Coursebook 2015 (A level)

P1: Practical skills at AS level
3 The apparatus shown in Figure P1.20 can be used to test the hypothesis that T, the time taken for a ball to roll down a plane from rest, is related to the distance s by the formula T 2 = ks, where k is a constant. The ball is timed using a stopwatch over two different values of s.
s
Figure P1.20 For end-of-chapter Question 3.
Suggest problems with the experiment and how they might be overcome. You should consider problems
in measuring the distance as well as the time. Also note what happens to the ball; it may not roll in the
way that you expect. [8]
Questions 4-6 are designed to illustrate some aspects of practical questions. They are not formal practical questions as, ideally, you should perform the experiment yourself and take some readings. This helps
you to see the problems.
4 An experiment explores the relationship between the period of a vibrating spring and the mass m in a pan holder. The student is instructed to set up the apparatus as in Figure P1.21, with a mass of 200 g in the pan. He is then told to move the pan downwards by approximately 1 cm and to release it so that it vibrates in a vertical direction.
clamp spring
mass
pan to hold masses
Figure P1.21 For end-of-chapter Question 4.
The student is asked to record the time taken for 20 oscillations of the spring, and then to repeat the procedure, using masses between 20 g and 200 g until he has six sets of readings. Columns are provided in the table for m and T, the period of the pendulum.
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