Question

A series of pulse of amplitude 0.15 m are sent down a string that is attached to a post at one end. The pulses are reflected at the post and travel back along the string without loss of amplitude. What is the amplitude at a point on the string where two pulses are crossing, (a) if the string is rigidly attached to the post? (b) if the end at which reflection occurs is free to slide up and down?

I have no clue srry

If rigid, it comes back opposite phase, so they cancel. If loose, it comes back in phase, so they add.

http://www.kettering.edu/~drussell/Demos/reflect/reflect.html

umm like i looked at it..i don't get what u mean it cancels out still..like are we supposed to use a formula?

No formula needed. Unless, you have difficulty understanding 1-1= cancel, and 1+1= twice amplidtude. :)