The amplitude of a wave corresponds to its maximum oscillation of the wave itself.
In our problem, the equation of the wave is
![y(x,t)= (0.750cm)cos(\pi [(0.400cm-1)x+(250s-1)t])](https://tex.z-dn.net/?f=y%28x%2Ct%29%3D%20%280.750cm%29cos%28%5Cpi%20%5B%280.400cm-1%29x%2B%28250s-1%29t%5D%29)
We can see that the maximum value of y(x,t) is reached when the cosine is equal to 1. When this condition occurs,

and therefore this value corresponds to the amplitude of the wave.
Something hot like a fire , an eye of a stove , and the sun
Their combined momentum after they meet is 0 .
As per impulse momentum theorem we know that

now here we will have

t = 1.30 ms
m = 0.144 kg

now we need to find final speed using above formula


so final speed is given as above