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ruslelena [56]
4 years ago
5

A boat takes 4.0 h to travel 36 km down a river, then 5.0 h to return.how fast is the river flowing

Physics
1 answer:
dem82 [27]4 years ago
5 0
<span>Let us refer to boat speed as X and water speed as Y On the way down the stream, the water speed is added to the speed of the boat: speed of the boat (X) + water speed (Y) is 9km/h When the boat is moving upstream, water speed is taken away from the speed of the boat: Speed of the boat (X) - water speed (Y) is 7.2 km/h Therefore: X + Y = 9 : X - Y = 7.2 2X = 16.2 X = 8.1 X + Y = 9 8.1 + Y = 9 Y = 0.9 The river is flowing at 0.9 km/h</span>
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Volume of an block is 5 cm3. If the density of the block is 250 g/cm3, what is the mass of the block ?​
wlad13 [49]

Answer:

The mass of the block is 1250g.

Explanation:

Given that the formula for density is ρ = mass/volume. Then you have to substitute the values into the formula :

ρ =  \frac{mass}{volume}

Let density = 250,

Let volume = 5,

250 =  \frac{m}{5}

m = 250 \times 5

m = 1250g

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3 years ago
What happens when you dip open bottle in bucket full of water?why​?<br>chapter=pressure​
Degger [83]

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Explanation: This happens because the bottle is empty and the bucket is full of water.

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3 years ago
One of the largest planes ever to fly, and the largest to fly frequently, is the Ukrainian-built Antonov An-124 Ruslan. The grav
Lerok [7]

Answer:

m = 236212 [kg]

Explanation:

The potential energy can be determined by means of the product of mass by gravity by height. In this way, we have the following equation.

P=m*g*h\\

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m = mass [kg]

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Now, we can clear the mass from the equation above:

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4 0
3 years ago
Assume that the polymer material has a constant refractive index of 1.5. For light of 600nm wavelength at normal incidence, what
yaroslaw [1]

Answer:

Minimum thickness will be 100 nm

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3 years ago
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4 0
3 years ago
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