What action could be taken to produce a longitudinal wave with high amplitude

What is the measurement of how fast an object moves relative to a reference point?

4. if you were an astronaut on the moon, what would you experience? what would you see from your perspective?

The experiment done in lab is repeated, using a ball that has unknown mass m. you plot your data in the form of f 2 versus m/l, with f in rev/s, m in kg, and l in m. your data falls close to a straight line that has slope 3.19 m/(kg · s2). use g = 9.80 m/s2 and calculate the mass m of the ball.