The moon and the Earth attract each other, with equal gravitational forces.
That may not sound too surprising.
But what do you think of THIS one:
-- You and the Earth attract each other, with equal gravitational forces.
-- Your weight on Earth is the same as the Earth's weight on you.
I can help you with that if you translate to English
However instead of crests and troughs, longitudinal waves have compressions and rarefactions. Compression. A compression is a region in a longitudinal wave where the particles are closest together. Rarefaction. A rarefaction is a region in a longitudinal wave where the particles are furthest apart.
Answer:
12.5 m/s
Explanation:
The motion of the hammer is a free fall motion, so a uniformly accelerated motion, therefore we can use the following suvat equation:

Where, taking downward as positive direction, we have:
s = 8 m is the displacement of the hammer
u = 0 is the initial velocity (it is dropped from rest)
v is the final velocity
is the acceleration of gravity
Solving the equation for v, we find the final velocity:

So, the final speed is 12.5 m/s.