1. A progressive wave in a stretched string has a speed of 20 ms and a frequency of 100 Hz. What is
the phase difference between two points 25 mm apart?
A zero
B pi/4 rad
c pi/2 rad
D pi tad

What should the power status of a circuit be when measuring resistance with an ohmmeter?

Consider a system with two masses that are moving away from each other. why will the kinetic energy differ if the frame of reference is a stationary observer or one of the masses?

22. the top of a cliff is located a distance h above the ground. at a distance h/2 there is a branch that juts out from the side of the cliff, and on this branch a bird's nest is located. two children throw stones at the nest with the same initial speed, one stone straight downward from the top of the cliff and the other stone straight upward from the ground. in the absence of air resistance, which stone hits the nest in the least amount of time?