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Galina-37 [17]
3 years ago
9

A boat moving at 7.8 km/hr relative to the water is crossing a river 3.5 km wide in which the current is flowing at 2.8 km/hr. A

t what angle upstream should the boat head to reach a point on the other shore directly opposite the starting point?

Physics
1 answer:
Free_Kalibri [48]3 years ago
8 0

Answer:\theta =21.03^{\circ}

Explanation:

Given

velocity of boat with respect to river =7.8 km/hr

velocity of river is 2.8 km/hr

River is 3.5 km wide

Suppose boat leaves at an angle of \theta  with vertical such that it reaches exactly opposite end of initial Point

Therefore

7.8\sin \thetacomponent will balance the river Flowso that sin component helps to cross the river

7.8\sin \theta =2.8

\sin \theta =0.3589

\theta =sin^{-1}(0.3589)

\theta =21.03^{\circ}

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Answer:

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= .382

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heat input of second engine = 4710 - 1229.15 = 3480.85

output of work of second engine

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4 years ago
As you stand near a railroad track, a train passes by at a speed of 31.7 m/s while sounding its horn at a frequency of 218 Hz. W
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Explanation:

Given that,

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Speed of train, v_t = 31.7 m/s

The speed of sound, V = 344 m/s (say)

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(a) When the train approaches you, the Doppler's effect gives the frequency as follows :

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(b) When the train moves away from you, the Doppler's effect gives the frequency as follows :

f'=f(\dfrac{V}{V+v_t})\\\\f'=218\times (\dfrac{344}{344+31.7})\\\\f'=199.6\ Hz

Hence, this is the required solution.

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4 years ago
The base ( foundation ) of building is made wider. Why ?​
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Explanation: ...

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2 years ago
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irakobra [83]

Answer:

F/2

Explanation:

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Hence;

F= KQ1Q2/r^2 ------(1)

Where the charge on Q1 is doubled and the distance separating the charges is also doubled;

F= K2Q1 Q2/(2r)^2

F2= 2KQ1Q2/4r^2 ----(2)

F2= F/2

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A 70.0 kg ice hockey goalie, originally at rest, has a 0.170 kg hockey puck slapped at him at a velocity of 33.5 m / s . Suppose
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