A 450-g black crow is raiding the recently-filled bird feeder. As someone runs out the back door to scare the crow away, it pushes off the 670-gram feeder with a takeoff speed of 1.5 m/s. Determine the speed at which the feeder initially recoils backwards.

2.50 m/s

Explanation:

This question can be solved using momentum conservation equation

combined mass of crow and feeder = 450+670=1120 gm

let the recoil speed of feeder be v m/s

Then applying momentum conservation we get;

1120*1.5 = 670*v

v = 2.50 m/s

the speed at which the feeder initially recoils backwards = 2.50 m/s