41. During a game of billiards, the 300 g cue ball, travelling at 2.1 m/s, glances off a stationary 280 g billiard ball so that the billiard ball moves off at 1.4 m/s at an angle of 38 from the cue ball's original path. Find the new speed of the cue ball. [3 marks] 42. Calculate the electric potential a distance 5.6 x 104 km from a point charge of 73.6 x 104 C. [3 marks] 43. In predicting the motion of tsunamis generated in the sea, and interacting with shoreline objects. A ripple tank is used to generate straight waves in region A that travel toward region B, which is separated from region A by a straight boundary. The frequency of the generator is 2.5 Hz, and the waves travel in region A with a speed of 15 cm/s. If the wave fronts in region A strike the boundary at 20, and the wave fronts in region B leave the boundary at 50. [4marks] (a) use Snell's law to find the relative index of refraction between the two regions (2) (b) find the wavelength in each region (2)