BIO Bird Defense.? To protect their young in the nest, peregrine falcons will fly into birds of prey (such as ravens) at high speed. In one such episode, a 600-g falcon flying at 20.0 m/s hit a 1.50-kg raven flying at 9.0 m/s. The falcon hit the raven at right angles to its original path and bounced back at 5.0 m/s. (These figures were estimated by the author as he watched this attack occur in northern New Mexico.) (a) By what angle did the falcon change the raven’s direction of motion? (b) What was the raven’s speed right after the collision?

Solution 40E Step 1 of 3: a)The collision forces are large so gravity can be neglected during the collision. Therefore, the horizontal and vertical components of the momentum of the system of the two birds are conserved. The system before and after the collision is shown in diagram. There is no external force on the system so p = p and p = p 1 x 2 x 1 y 2y p 1 x= p2 x (1.5 kg)(9 m/s) = (1.5 kg)v raven 2os and v raven 2cos = 9 m/s p 1 y= p2 y (0.600 kg)(20 m/s) = (0.600 kg)( 5 m/s) + 1.5 m/s v raven 2n and v raven 2in = 10 m/s combining these two equations tan = 10 m/s 9 m/s = 1.11 1 = tan (1.11) 0 = 48 Step 2 of 3: b) v = 13.5 m/s raven 2