Please help with this, oh and bungee gum contains both the properties of rubber AND gum you see?

Atransverse wave is traveling on a string stretched along the horizontal x-axis. the equation for the vertical displacement y of the string is given by y = (1.8 x 10-3)cos[π(13x - 60t)], where all quantities are in si units. what is the maximum speed of a particle of the string

The slotted link is pinned at o, and as a result of rotation it drives the peg p along the horizontal guide. compute the magnitude of the velocity and acceleration of p along the horizontal guide. compute the magnitudes of the velocity and acceleration of p as a function of θ if θ=(3t) rad, where t is measured in seconds.

Modern physics a photon emitted from an excited hydrogen atom has an energy of 3.02 electron volts. which electron energy-level transition would produce this photon? a. n=1 to n=6 b. n=2 to n=6 c. n=6 to n=1 d. n=6 to n=2 i chose b but the correct answer is d can someone tell me why? and what's the difference?