Checkpoint $17\mathrm{.}3\mathrm{.}1$

Here are three pairs of sound waves. The waves in each pair are sent along the same axis so that they undergo interference. Rank the pairs according to the amplitude of the resultant wave, greatest amplitude.

Pair $A$ :

$s_1(x,t)=s_{m}cos(kx-t)$

$s_2(x,t)=s_{m}cos(kx-t+0\mathrm{.}90)$

Pair B:

$s_1(x,t)=s_{m}cos(kx-t)$

$s_2(x,t)=s_{m}cos(kx-t+1\mathrm{.}10)$

Pair $C$ :

$s_1(x,t)=s_{m}cos(kx-t)$

$s_2(x,t)=s_{m}cos(kx-t+0\mathrm{.}20)$