1. The problem statement, all variables and given/known data In a pile driver , a steel hammerhead with mass 200kg is lifted 3m above the top of a vertical I beam being driven into the ground. the hammer is then dropes driving the Ibeam7.4cm farther into the ground. The vertical rails that guide the hammerhead exert a constant 60N friction force on the hammerhead. Use the work energy theorem to find a) speed of the hammerhead just as it hits the I beam and b) the average force the hammerhead exerts on the I-Beam Ignore the air effects of the air. 3. The attempt at a solution I managed to understand part a. Part b is where I am lost. The book shows the following work, and I need help understanding on of the steps. Wtotal = (w-f-n)s23 Wtotal = (w-f-n)s23 = k3-k2 *** n is the same as g right? and we solve for n? Since when is n the average force?*** n = w-f - k3-k2/s23 =1960N - 60N - 0J - 5700J / 0.074m =7900N the part underlined I understand. The part in bold is where I can't explain why.