The figure below shows the displacement-time graph of a wave travelling at 0.4ms−1 displacement time graph of wave travelling at 0.4 How many complete waves are shown? Determine the period time of the wave

Question

The figure below shows the displacement-time graph of a wave travelling at 0.4ms⁻¹

1. How many complete waves are shown? 
2. Determine the period time of the wave 

Answer 1

1. 2
2. Time=0.45