D: Velocity is decreasing. Acceleration is increasing.
A: Velocity is zero.
The pendulum starts from rest at A, hence the velocity of pendulum at A is zero.
So velocity is zero at A
As the pendulum swings from A to E, it first gains speed from A to C and the speed decreases from C to E coming to a momentary stop at E.
Similarly, as the pendulum swings from A to E, the acceleration first decreases A to C (becoming zero at C) and the acceleration increases from C to E coming to a maximum at E.
So
D: Velocity is decreasing. Acceleration is increasing.
6.84m
Explanation:
The question you asked didn't specify the frequency of the instrument, so I'm going to assume for the question sake.
For the question, we will use the formula
λ = V/F, where
λ = the wavelength we're looking for
V = Velocity of the sound
F = frequency of sound.
Assuming that the frequency of the instrument is 50Hz.
λ = 342/50
λ = 6.84 m