How would you describe the amplitude of a wave using the words crest and trough?

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?

Identify the correct relation showing that the radius r of the orbit of a moon of a given planet can be determined from the radius r of the planet, the acceleration of gravity at the surface of the planet, and the time τ required by the moon to complete one full revolution about the planet. determine the acceleration of gravity at the surface of the planet jupiter knowing that r = 71 492 km and that t= 3.551 days and r= 670.9 × 10^3 km for its moon europa.

Is the vertical component of velocity ever zero?