4. How long would it take for a water balloon to fall 39 m if we dropped it starting from rest down an elevator shaft from the 13th floor? Ignore air resistance and use a = -9.8 m/s2.
x, = x + vt + (1/2) a t?

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.

Amira pulls a 3 pound wagon 4 feet. how much work has she done?

The amount of work done is determined by 2 factors. describe an example of work (using the scientific definition) list the 2 factors that determine the amount of work done.