Question

A river is flowing with a speed of 1 km/hr. A swimmer wants to go to point
'C' starting from 'A'. He swims with a speed of 5 km/hr, at an angle o w.r.t.
the river. If AB = BC = 400 m. Then the value of 0 is:​

Answer 1

Answer:

A river is flowing with a speed of 1 km/hr. A swimmer wants to go to point

'C' starting from 'A'. He swims with a speed of 5 km/hr, at an angle o w.r.t.

the river. If AB = BC = 400 m

The figure is attached.

Explanation:

Since AB=BC

By using  vector addition:

5sinθ=5cosθ +1

5(sinθ−cosθ)=1

sinθ−cosθ=1/5

or θ=53°

The time taken t= AB/5sinθ

t=0.400/5×4/5

=1/10hrs

=6mins

Answer 2

Answer:53

Explanation:

Condition for reaching the point C tan45∘=vyvx,vy=vx

(vR+vMcosθ)=vMsinθ

1+5cosθ=5sinθ

1+5cosθ=51−cos2θ−−−−−−−−√

On squaring. 1+25cos2θ+10cosθ=25−25cos2θ

50cos2θ+10cosθ−24=0