Chapter 8, Problem 8.106PP

BIO MOMENTUM AND THE ARCHERFISH. Archerfish are tropical fish that hunt by shooting drops of water from their mouths at insects above the water’s surface to knock them into the water, where the fish can eat them. A 65-g fish at rest just at the surface of the water can expel a 0.30-g drop of water in a short burst of 5.0 ms. High-speed measurements show that the water has a speed of 2.5 m/s just after the archerfish expels it.

8.106 What is the momentum of one drop of water immediately after it leaves the fish’s mouth? (a) 7.5 × 10 ⁻⁴ kg · m/s; (b) 1.5 × 110⁻⁴ kg · m/s; (c) 7.5 × 10⁻³ kg · m/s; (d) 1.5 × 10⁻³ kg · m/s.