contestada

A 0.14-km wide river flows with a uniform speed of 4.0 m/s toward the east. It takes 20 s for a boat to cross the river to a point directly north of its departure point on the south bank. What is the speed of the boat relative to the water

Respuesta :

Cricetus

Answer:

The right approach is "8.1 m/s". A further explanation is provided below.

Explanation:

According to the table,

Speed of Boat

= [tex]\frac{s}{t}[/tex]

[tex]V_b=\frac{140}{20}[/tex]

[tex]V_a = 4 \ m/s[/tex]

[tex]V_B = 7 \ m/s[/tex]

Now,

⇒  [tex](V_{relative})^2 = (7)^2+(4)^2[/tex]

or,

⇒  [tex](V_r)^2=49+16[/tex]

              [tex]=65[/tex]

         [tex]V_r=\sqrt{65}[/tex]

              [tex]=8.1 \ m/s[/tex]

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