a lighthouse, facing north, sends out a fan-shaped beam of light extending fron north-east to north-west. An observer on a steamer, sailing due west, first sees the light when he is 5 km awayfrom the lighthouse, and contonues to see it for 30 x sqrt.2 minutes. What is the speed of the steamer...?
Ans... 10 km/h
Amit Saxena , 13 Years ago
Grade upto college level
1 Answers
Chetan Mandayam Nayakar
Last Activity: 13 Years ago
if you draw the diagram(which is a very elementary thing to do) you will realize that the steamer travels 5√2 km when the observer is seeing the light. therefore speed=distance/time=5√2/(√2/2) km/h=10 km/h
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