4 11969.03 Question 1 Requirements • Extension (disposable) spring unextended length 20 mm • 100 g mass holder × 2 • 100 g slotted mass × 4 • Half metre rule • Retort stand, boss head & clamp • Labels Preparation Connect the boss head and clamp to the retort stand. Before the examination Suspend the unextended spring from the clamp. Place one 100 g mass onto a 100 g mass hanger, label this ‘200g’. Place three 100 g masses onto the other mass hanger, label this ‘400g’. Set these beside the retort stand. Set the half metre rule close to the retort stand. Action at changeover Return the apparatus to the original arrangement on the bench.