Question

9.A man while walking on a horizontal road with a velocity of 10 km/hobserves the rains to be falling vertically downward. If he increases hisspeed to 20 km/h, then the rain drops appear to strike him at an angleof 45 from vertical. What is then actual velocity of the rain drops?dec​

Answer 1

Answer:

10√2 km/Hr

Explanation:

A man while walking on a horizontal road with a velocity of 10 km/h observes the rains to be falling vertically downward. If he increases his speed to 20 km/h, then the rain drops appear to strike him at an angle of 45 from vertical.

Let say Rain falling with velocity V at angle α with Ground

=> Horizontal Velocity = VCosα

& Vertical Velocity  = VSinα

VCosα =  10 km/Hr ( as Man with a velocity of 10 km/h observes the rains to be falling vertically )

he increases his speed to 20 km/h, then the rain drops appear to strike him at an angle of 45 from vertical.

=> Tan 45  = Vsinα/(20 - VCosα)

=> 1 = VSinα/(20 - 10)

=> VSinα = 10

V = √V²Cos²α + V²Sin²α  = 10√2

actual velocity of the rain drops = 10√2 km/Hr

Answer 2

Answer:

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