Note that because of the reflection, the pulse has traveled twice the length of the rope. The wave velocity or speed is thus 30ft. Your Answer to Q24. You should try to work out the answer on your own, but if you insist on reading it the correct answer is here. In this case the cycle is one motion down and back up to the starting point.
Frequency is the number of cycles in one second.
The bob makes 40 cycles in 10 seconds. 4 cycles per second or 4 Hertz. Your Answer to Q 25. Sorry, your answer is not correct. Click on HELP below to transfer there.