❗❗100points❗❗ Hey can any1 tell me how I answer question a, I just don't understand what am supposed to write, can sb explain it?? thanks ♡

Your target variable is δf, the magnitude of the difference in frequency between the waves emitted from the sonar device and the waves received by the device after reflecting off the whale. write an expression for δf in terms of the relevant frequencies using the subscript notation introduced above.

Why do astronauts in the space shuttle weigh less?

Aperson touches a large chunk of ice with their hand and remarks, “this is making me cold.” explain what this person is feeling. is the ice transferring “cold” to the person? is there a heat transfer occurring? explain.