Answer:
Step-by-step explanation:
Here we know that pile will go down under gravity for d = 4.20 m before coming in contact with beam
Now after being in contact with the beam the pile further go down by L = 15.4 cm.
Finally it will come to rest.
So here we can say that work done by gravity + work done by beam on the pile must be equal to change in its kinetic energy
So here we have