1) What was the precision of the individual bird mass measurements? What is the simplest instrument that you have used that will give you the same precision? 2) Why did the authors mention that they calibrated the sensors with static weights before and after each run? 3) They measure the force on the perch, how is this related to the pushing force of the bird's legs on its body? Which basic principle of classical physics is this relationship an example of? 4) In figure 1 the zoologist makes an error, what is it? 5) Draw a free body diagram of the bird and use the measurements of the average vertical force and the average mass of the bird to check the zoologist's calculation of the maximum vertical acceleration. 6) The zoologist makes a statement: "This acceleration would propel the bird to a height of approximately 3 cm above the perch". How would you rephrase it so that it makes more sense to someone educated in physics