Compute all parts of following problem:
Problem: A bat moving with speed of 3.25 m/s and emitting sound of 35.0 kHz approaches a moth at rest on a tree trunk.
Part A: What frequency is heard by the moth?
Part B: If the speed of the bat is increased, is the frequency heard by the moth higher or lower?
Part C: Calculate the frequency heard by the moth when the speed of the bat is 4.25 m/s.
I need help to calculate the frequency heard by the moth.