C: "The students pass the envelope from one student to the next until it travels across the room."
To quote ck12, "The particles of the medium just vibrate in place. As they vibrate, they pass the energy of the disturbance to the particles next to them, which pass the energy to the particles next to them, and so on."
Given
velocityΔ v₁ = 6m/s
v₂ = 11m/s
Δ time = Δ t = 2s
sign / indicate as division.
acceleration a = Δv/ Δt
a = (v₂-v₁) / Δt
a = (11m/s -6m/s ) / 2s
a = (5m/s) / 2s
accerelation a = 2.5m