You throw a ball straight up into the air at a speed of 15 m/s.  you want to know how high above your hand the ball will be at exactly 2.5 sec after you released it. 

Light traveling in water, nwater = 1.33, strikes a plastic block at an angle of incidence of 51.4°; part of the beam is reflected and part is refracted. if the index of refraction of the plastic is 2.0, what is the angle made by the reflected and refracted beams?

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?

Wind and moving water provide energy. question 1 options: chemical mechanical thermal none of the above