Question

a river is flowing with speed of 8 km/h . a swimmer wants to reach a point R from P. he swims with constant speed of 8km/h at an angle theta equal to or less then 90degree wet river flow. if PQ=QR=800m then value of theta is...​

Answer 1

Answer:

a river is flowing with speed of 8 km/h . a swimmer wants to reach a point R from P. he swims with constant speed of 8km/h at an angle theta equal to or less then 90degree wet river flow. if PQ=QR=800m then value of theta is...​

Explanation:

Answer 2

Swimmer is Swimming at an angle of 90° to river Flow  if PQ = QR = 800m

Explanation:

Swimmer Speed in Direction of River flow

= 8 Cosθ

so Net Speed of Swimmer in River Direction = 8  + 8 Cosθ

Speed of Swimmer in direction of point Q = 8Sinθ

Let say Time Taken = T

Distance PQ  = 8Sinθ * T

Distance QR  = (8  + 8 Cosθ)*T

=> 8Sinθ * T = (8  + 8 Cosθ)*T = 800 m

=>  8Sinθ = 8  + 8 Cosθ

=> Sinθ - Cosθ = 1

=> θ = 90°

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