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2 years ago

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Jada is rowing a boat across a river that has a current of 5 m/s in the ˆ j direction. Leanne, standing on the shore, observes J

ada’s velocity to be 8 m/s ˆ I + 3 m/s ˆ j.
What is Jada’s speed with respect to the water?
a. 13.3 m/s
b. 11.3 m/s
c. 8.54 m/s
d. 8.25 m/s
e. 4.24 m/s
f. None of these

1 answer:

olchik [2.2K]2 years ago

5 0

Answer: d. 8.25 m/s

Explanation:

We are given that Current= 5 m/s in j direction

Velocity= 8 m/s i + 3 m/s j

Now, we have to find Jada's speed with respect to the water.

First we find Jada's velocity with respect to water

v= (8 i + 3 j) - (5 j)

v= 8i - 2 j

To find the speed, we take the magnitude of this velocity vector we have

|v|= $\sqrt{(8)^2+(-2)^2}$

|v|= $\sqrt{68}$ = 8.246 m/s

which comes out to be around = 8.25 m/s

So option d is correct.

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Answer:

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Explanation:

From the question we are told that

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substituting values

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$V_w = \frac{V}{2}$

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$V_w = \frac{1162.7 }{2}$

$V_w = 581.4 \ dm^3$

mass of water been displaced by the this volume is

$m_w = V_w$ According to Archimedes principle

=> $m_w = 581.4 \ g$

$m_w = 0.5814 \ kg$

The weight of the water displace is

$W _w = m_w * g$

$W _w = 0.5814 * 9.8$

$W _w = 5.698 \ N$

The actual weight of the rock is

$W_r = m_r * g$

$W_r = 5.0 * 9.8$

$W_r = 49.0 \ N$

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$T = 49.0 - 5.698$

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You replace the expression (1) into the expression (2):

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You do the constant c in the last equation, then you replace the values of v, s and Δs:

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the specific heat of water is 4.2 j/c. if it takes 31,500 joules to heat to warm 750 g of water, what was the temperature change

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