Question

A hungry 11.5 kg predator fish is coasting from west to east at 75.0 cm/s when it suddenly swallows a 1.25 kg fish swimming from north to south at 3.60 m/s. 1. Find the magnitude and dir ection of the velocity of the large fish just after it snapped up this meal. Neglect any effects from "water drag.2. Find the direction of the velocity of the large fish just after it snapped up this meal.

Answer 1

Answer with Explanation:

We are given that

Mass,m=11.5 kg

$v_x=75 cm/s=0.75 m/s,v_y=0$

1 m=100 cm

$m'=1.25 kg$

$v'_x=0,v'_y=3.6 m/s$

According to law of conservation momentum along east west direction

$11.5\times 0.75+1.25(0)=(11.5+1.25)V_x$

$8.625=12.75V_x$

$V_x=\frac{8.625}{12.75}$

$V_x=0.68 m/s$

According to law of conservation of momentum along north south direction

$11.5(0)+1.25(3.6)=(11.5+1.25)V_y$

$4.5=12.75V_y$

$V_y=\frac{4.5}{12.75}=0.35 m/s$

$V=\sqrt{V^2_x+V^2_y}$

$V=\sqrt{(0.68)^2+(0.35)^2}$

$V=0.76 m/s$

Direction,$\theta=tan^{-1}(\frac{V_y}{V_x})$

$\theta=tan^{-1}(\frac{0.35}{0.68})$

$\theta=27.23^{\circ}$