MasteringPhysics: 08B -Google Chrome Secure l https://session.masteringphysics.c
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Question
MasteringPhysics: 08B -Google Chrome Secure l https://session.masteringphysics.com/myct/itemView?assig 08B Exercise 8.40 Constants 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 570 g falcon flying at 19.0 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.)Explanation / Answer
here,
initial speed of falcon , u1 = 19 m/s i
m1 = 0.57 kg
mass of raven , m2 = 1.5 kg
initial speed of raven , u2 = 9 m/s j
final speed of falcon , v1 = -5 m/s i
let the final speed of raven be v2
using conservation of momentum
m1 * u1 + m2 * u2 = m1 * v1 + m2 * v2
0.57 * 19 i + 1.5 * 9 j = 0.57 * (-5) i + 1.5 * v2
solving for v2
v2 = 9.12 i + 9 j m/s
a)
the angle changed , theta = 90 - arctan(9/9.12) = 45.4 degree
b)
the speed of raven after the collison , |v2| = sqrt(9.12^2 + 9^2)
|v2| = 12.8 m/s