Calculate the velocity of a water wave if the frequency is 390 hz, the wavelength is 5.2m, and the amplitude of the wave is 3.76cm

Blank liquids and gases exert a buoyant force on objects placed in them

Students design a model roller-coaster track. they place a rubber ball at the highest point on the track and let it go. the ball rolls along the track pulled only by the force of gravity. eventually, it comes to a stop. which change to the design will result in the ball moving the greatest distance?

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.