Question

A sailor in a boat which is going due east with a speed of 8m/s , observes that a submarine is heading towards north at a speed of 12m/s and sinking at a rate of 2 m/s. the commander of submarine observes a helicopter ascending at a rate of 5m/s and heading towards west with 4m/s find the actual speed of the helicopter and its speed w.r.t boat

Answer 1

let the direction of  East be denoted by x axis with unit vector i.
let the direction of North be y axis with  unit vector k.
Let the vertical direction be  z axis with u v = k.

b = boat,   sb = submarine wrt boat,  hb = helicopter wrt boat

Vb = 8 i  m/s 
Vsb = 12 j - 2 k  m/s
=>  Vs = Vsb + Vb = 12 j + 8 i - 2 k   m/s 
 =>  speed = 2√53  m/s

Vhs = 5 k - 4 i
=> Vh = Vhs + Vs = 4 i + 2 j + 3 k
=>  Magnitude = √29  m/s

Vhb = Vh - Vb = -4 i + 2j + 3 k
    => magnitude of speed = √29 m/s

Answer 2

Answer:

Explanation:ans no 6