a tennis ball is thrown straight up with an initial velocity of 22.5 m/s how much total time is the ball in the air

What would the difference of spectral lines emitted by hydrogen gas in distant galaxies which is normally found at a wavelength of 21 cm on earth, be observed at 21.1 centimeters?

Astone dropped into a well is heard to strike the water after 8seconds. find the depth of the well if the velocity of sound is 350m/s

What is the average speed of a car that travels 40 mph for 1 hour and 60 mph in another hour?