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svp [43]
3 years ago
12

A boat crosses a 200m wide river at 3m/s, north relative to water. The river flows at 1m/s as shown. What is the velocity of the

boat as observed by a stationary observer on the river back from the boat departed?
Physics
1 answer:
Xelga [282]3 years ago
3 0

Answer:

The resultant velocity = 3.16 m/s

Explanation:

Since the boat is moving North of the direction of the riverflow, the river would either be flowing westward or Eastward. The two motions form a right angle triangle with the resultant velocity being the hypotenuse of the traingle.

The resultant velocity will be given as ;

R² = B² + r²

Where B is the velocity of the boat and r is the velocity of the river

R² = 3² + 1²

R² = 10

R = √10 = 3.16 m/s

Therefore, the resultant velocity = 3.16 m/s

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4 0
3 years ago
A stationary police car emits a sound of frequency 1240 HzHz that bounces off of a car on the highway and returns with a frequen
lara [203]

Answer:

frequency =  1475.45 Hz

Explanation:

given data

frequency f1 = 1215 Hz,

frequency f2 = 1265 Hz

police car moving vp = 25.0 m/s

solution

speed of sound u = 343 m / s

speed of the other car = v

when the police car is stationary

the frequency the other car receives is

f2 =  f1  ×  \dfrac{u+v}{u}      ................1

and

the frequency the police car receives is

 f2 =  f1  ×  \dfrac{u}{u-v}      ..................2

now from equation 1 and 2

\frac{f2}{f1} = \dfrac{u+v}{u-v}

 \frac{1275}{1240} = \frac{u+v}{u-v}

v =\frac{1275-1240}{1275+1240}\times 343  

v = 4.77 m/s

and

frequency the other car receives is  

f2 = f1 ×   \dfrac{u+v}{u-vp}       ......................3

and

the frequency the police car receives is

f2 = f1 ×  \dfrac{u+vp}{u - v}       .......................4

now we get

f2 = f1 ×  \dfrac{(u+v)(u + vp)}{(u-v)(u-vp)}      

f2 =    1240\times \frac{(343+4.77)(343+25)}{(343-4.77)(343-25)}        

f2 =  1475.45 Hz

 

4 0
3 years ago
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4 0
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A glider is gliding through the air at a height of 416 meters with a speed of 45.2 m/s. The glider
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There's not enough information to find an answer.

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3 0
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