Answer:
3100 m/s
Explanation:
The relationship between frequency and wavelength of a wave is given by the wave equation:

where
v is the speed of the wave
f is its frequency
is the wavelength
For the wave in this problem,
f = 15,500 Hz

Therefore, the wave speed is

I searched for you and i think its Velocity. it would be nice if u put the answer choices though
Acceleration = (final velocity - initial velocity) / time
= (35-65)/10
= -3 m/s2