Question

Match the following columns.

Column I	Column II
(a) It is raining verticaly at 2√3 m s–1. If wind blows horizontally at 2 m·s–1, . The apparent velocity of rainfall is —	(p) 20 m·s–1
(b) A boat is moving at 12 m·s–1 towards north and another boat is moving at 12√2 m·s–1 towards north-west. Find the relative velocity of the second boat with respect to the first is equal to —	(q) 150 m·s–1
(c) From the top of a tower, two particles are dropped at an interval of 2s. Find the relative velocity and relative acceleration of the particles during the fall. Acceleration due to gravity = 10 m·s–2.	(r) 4 m·s–1
(d) A police jeep is chasing with velocity of 12.5 m·s–1 a thief in another jeep moving with velocity 42.5 m·s–1. Police fires a bullet with muzzle velocity of 180 m·s–1. The velocity with which it will strike the car of the thief is —	(s) 12 m·s–1

Answer 1

Correct option (d) 

Explanation:

(a) → (r) ; (b) → (s) ; (c) → (p) ; (d) →(q)

(d) Effective speed of the bullet 

 = speed of bullet + speed of police jeep 

 = 180 m·s^–1 + 12.5 m·s^–1 = (180 + 12.5) m·s^–1 = 192.5 m·s^–1 

 speed of thief's jeep = 42.5 m·s^–1 

 Velocity of bullet w.r.t thief's car 

= 192.5 – 42.5 = 150 m·s^–1