Jitender Singh
Last Activity: 10 Years ago
Ans: 6 km/hr
Let ‘x’ be the distance of the man from the lamp post at any moment & ‘l’ be the length of the shadow formed.
Distance of man from lamp post = x km
Distance of shadow from lamp post = (x+l) km
Height of the man = 1.5 km
Height of lamp post = 4.5 km
Using similar triangles, we have
Differentiate on both sides, we have
Velocity of shadow:
Thanks & Regards
Jitender Singh
IIT Delhi
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