What does sound need to travel?

Aball is thrown straight up into the air with a speed of 21 m/s. if the ball has a mass of 0.1 kg, how high does the ball go? acceleration due to gravity is g = 9.8 m/s^2. a. 22.5 m b. 20.0 m c. 25.0 m d. 17.5 m

What is the stall speed at sea level of an airplane that weights 10000 lbs., has a wing area of 300ft^2, and a maximum lift coefficient of 1.4? what is the stall speed if flaps that double cl,max are applied?

The force needed to overcome static friction is usually less than that needed to overcome kinetic friction.true or false?