The formula v=fλ can be used here.
326=2500*λ
Note the 2500 as 2.5kHz is 2.5 thousand Hz.
λ = 326/2500
= 0.1304m = 0.130m
According to Newton's 2nd law of motion:
F = m * a where F is the force applied in Newtons, m is the mass of the object in kg, and a is the acceleration of the object in m/

.
Therefore the force applied in this situation is simply:
F = 6 kg * 2.3 m/

= 13.8 N
Hope this helps!
He has tendonitis. Hope this helps
Explanation:
Below is an attachment containing the solution.
I think it D because I watched a video where the man did this exact same thing and the wave came back