B3. An 80 kg student is contemplating making a bungee jump from a platform 60 m above a canyon. Using an elastic bungee rope that is 30 m long when it is not loaded, and 35 m long when it supports his weight. (a) Calculate the spring constant of the bungee cord. I:]0 I:I% I:|1 For marking only (b) By considering energy before the student jumps, and again at the lowest point, calculate the height above the canyon oor that the student initially falls to when making the jump. H0 |_l% |_|1 |_|g I_|2 Ll; |_l3 |_|% |_|4 For marking only B4. A 110 g, 20 cm long wood block is dropped and falls downward as shown. 1.5 s after the block is dropped, it is hit by a 12 g bullet travelling upward at 220 m/s. The bullet becomes embedded in the block. The block's moment of inertia for rotation in the plane of the diagram, about its center of mass is 3.7 x10-4 kg.m2/s. (a) The bullet's trajectory is aligned with the block's center of mass. How close does the center of mass of the bullet/ block combination get to the original position from which the block was dropped? $ 1 2 For marking only (b) If the bullet's trajectory is still vertical, but aligned 8 cm to the left of the block's center of mass, how close does the center of mass of the bullet / block combination get to the original height from which the block was dropped? 8 cm