pring 2018 Final Exam vB )The graph to the right is a history h at x-4.0 m of a
ID: 2304008 • Letter: P
Question
pring 2018 Final Exam vB )The graph to the right is a history h at x-4.0 m of a wave traveling to ght at a speed of 3.0 m/s. Which is orrect history graph for a spot at 0 m? ? (cm) The wave atx4.0m s 0 24 6810 12 Ar fcm Ay (cm) r (s) 0246 8 10 122 46810 12 ial dy tcm) Ay (em) 02465 1012246S 1o2 idi he graphs below are a Snapshot and History graph for the sa eling on a stretched string. hot at r 0.01 s History -4 r (s) 0.02 0.04 0.06 Which direction is the wave traveling? Explain. (No points f hat is the speed of this wave?Explanation / Answer
2) x=-2 is 6m left to x=4 So clearly thewave has passed through x=-2 earlier than x=4 as teh wave is moving right. To find the history pick any point on the waveform let's say the rightmost point t=8. As the points are 6m apart the waveform will take 6/3=2s(distance /speed) to travel. Therefore whatever happens to the x=4 at t=8 must have happened to x=-2 2s before i.e. at t=8-2=6s. So rightmost part must be at t=6. similarly the leftmost part must be at t=4-2=2s. Therefore the second graph is correct.
3)A) The wave is travelling right. In the first graph t=0.01s and the waveform ranges from x=-6 to x=-2 while it reaches x=2 at t=0.03s so clearly it reach x=2 later than x=-2 therfore it is moving right.
B) From the first graph waveform has a length of 4cm as it strtches from x=-6 to x=-2. From the second graph, it takes 0.02 secons for the waveform to pass through a point. Therefore speed is 4/0.02=200cm/s=2m/s.