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olga55 [171]
3 years ago
9

On an ice skating rink, a girl of mass 50 kg stands stationary, face to face with a boy of mass 80 kg. The children push off of

one another, and the boy moves away with a velocity of 3 m/s. What is the final velocity of the girl? â€"1. 9 m/s 1. 9 m/s â€"4. 8 m/s 4. 8 m/s.
Physics
1 answer:
sasho [114]3 years ago
5 0

The velocity of the girl is  -4.8 m/s.

Using the principle of conservation of linear momentum, The total momentum of  bodies before and after collision is constant. Since the two objects are stationary, the initial momentum of each body is zero.

Thus;

0 = (80 × 3) + (50 × v)

0 = 240 + 50 v

-240 = 50 v

v = -240/50

v = -4.8 m/s

Note that the negative sign shows that the velocity of the girl is in opposite direction that that of the girl.

Learn more about momentum: brainly.com/question/904448

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Answer: 9 days

Explanation:

  • Step 1

Let the rate of Leaf growth <em>r</em> be defined as, \frac{Increase  in  area}{time taken} = \frac{A1 - A}{t}

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Given that rate of leaf growth, r is proportional to the surface area of the leaf A. we have r ∝ A.

r = kA, where k is the rate constant.

therefore, k = \frac{r}{A}

when A = 2cm^{2}, A1 = 3

so k = \frac{\frac{3 - 2}{3}}{2}

= \frac{1}{3} ÷ 2

= 0.33 ÷ 2

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0.33 = \frac{3}{t}.

t = 3/0.33

Therefore, t = 9 days.

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Looking at each fuel:

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The best fuel in terms of energy to volume ratio is Gasoline.
Gallons required:
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