a) In building a rocket launchpad, a pile driver hammer of mass 110kg falls freely through a distance of 5 m to strike a pile of mass 450kg and drives it 75 mm into the ground. The hammer does not rebound when driving the pile. Determine the average resistance of the ground using D" Alembert's principle. The principle of conservation of energy equates work done in a system to changes in potential energy, changes in kinetic energy, and other energy losses. D" Alembert's principle equates work done to the sum of all forces applied in a system. These are two alternatives, and sometimes complimentary, approaches. b) Validate the result from part a) above using the conservation of energy principle. ) Compare and contrast the two methods used in parts a) and b) in relation to the problem you are solving. Evidence you must produce for this task * All working out making clear any formulae used, making clear what is being calculated * ALL UNITS MUST BE SHOWN A written analysis of the two methods used ' - Criterion To achieve the criteria, you must show that you are able to: Determine the retarding force on a freely falling body when it impacts on a stationary object and is brought to rest without rebound, in a given distance Compare and contrast the use of D'Alembert's principle with - the principle of conservation of energy to solve an engineering