If a star is 50 light-years away from earth, how long will it take light to travel from star to earth?

Avery hard rubber ball (m = 0.5 kg) is falling vertically at 4 m/s just before it bounces on the floor. the ball rebounds back at essentially the same speed. if the collision with the floor lasts 0.05 s, what is the average force exerted by the floor on the ball?

Which type of microscope would allow the viewer to see ribosomes inside a cell?

What is created when solids,liquids,an gases mix with one another