Suppose you are biking side by side with a friend. write a short explanation that describes the motion of your friend? what information are you using to describe that motion?

What is the earliest point in the universe that we can observe? why can’t we see back further than this?

The difference between a red shift and a blue shift has to do with wavelength frequency. t or f

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.