Engineering mechanical principles help plss :dWatch
A pile driver hammer of mass 150kg falls freely through a distance of 5m to strike a pile of mass 400kg and drives it 75mm into the ground. The hammer does not rebound when driving the pile.
a. Calculate the velocity v1, of the hammer immediately before impact with the pile using the equation for linear motion.
Seems so simple but I don't know why I'm not getting it.