Paper 3: Required practical 7 - Simple Harmonic Motion

Question 1

When 2 conditions must be met when carrying out a simple harmonic motion experiment involving a pendulum?

Answer 1

1. Amplitude of oscillation should be small
2. The pendulum should oscillate in a straight line

Question 2

Why must the oscillations only be small?

Answer 2

The equations are derived using a small angle approximation and so only apply for relatively small displacements

Question 3

How should you measure the time period of an oscillating simple pendulum?

Answer 3

• Measure the time taken for the pendulum to complete 10 full oscillations
• Repeat this measurement three times and then calculate an average time
• Divide this by 10 to ascertain the average time period for one oscillation

Question 4

What could be added to the apparatus to help measure the time period more accurately?

Answer 4

A fiducial marker (small pin) could be added at the centre of oscillation to show exaclty when an oscillation has been completed

Question 5

When plotting a graph of T^2 against L, what does a straight line passing through the origin demonstrate?

Answer 5

Directly proportional

Question 6

How can gravitational field strength be estimated from a graph of T^2 against L?

Answer 6

4pi^2/gradient