' A ' and ' B ' are moving along same straight line in opposite direction, each with speed 4 m / s with respect to ground. 'A' sees that the rain drops are falling vertically while ' B ' sees the rain drops falling at an angle 45° with the vertical. The speed of rain w.r.t ground, is

Question

' A ' and ' B ' are moving along same straight line in opposite direction, each with speed 4 m / s with respect to ground. 'A' sees that the rain drops are falling vertically while ' B ' sees the rain drops falling at an angle 45° with the vertical. The speed of rain w.r.t ground, is (A) 4 √5 m / s (B) 4 √2 m / s (C) 4 m / s (D) 8 √2 m / s

Tardigrade Admin · Accepted Answer

⇒ V Rx = V A =4 m / s ldots (i) and

⇒ V Ry = V Rx + v B =8 m / s ldots...(ii) Speed of rain √(8)2+(4)2=4 √5 m / s

$45 m / s$

$42 m / s$

$4 m / s$

$82 m / s$

$\Rightarrow V_{R x} = V_{A} = 4 m / s \dots$ (i)
and

$\Rightarrow V_{R y} = V_{R x} + v_{B} = 8 m / s \dots$ ...(ii)
Speed of rain $(8)^{2} + (4)^{2} = 45 m / s$

Q. ' A ' and ' B ' are moving along same straight line in opposite direction, each with speed 4m/s with respect to ground. 'A' sees that the rain drops are falling vertically while ' B ' sees the rain drops falling at an angle 45∘ with the vertical. The speed of rain w.r.t ground, is

45​m/s

42​m/s

4m/s

82​m/s

⇒VRx​=VA​=4m/s… (i) and ⇒VRy​=VRx​+vB​=8m/s…...(ii) Speed of rain (8)2+(4)2​=45​m/s

$45 m / s$

$42 m / s$

$4 m / s$

$82 m / s$

$\Rightarrow V_{R x} = V_{A} = 4 m / s \dots$ (i)
and

$\Rightarrow V_{R y} = V_{R x} + v_{B} = 8 m / s \dots$ ...(ii)
Speed of rain $(8)^{2} + (4)^{2} = 45 m / s$