Answer:
M[min] = M[basket+people+ balloon, not gas] * ΔR/R[b]
ΔR is the difference in density between the gas inside and surrounding the balloon.
R[b] is the density of gas inside the baloon.
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Let V be the volume of helium required.
Upthrust on helium = Weight of the volume of air displaced = Density of air * g * Volume of helium = 1.225 * g * V
U = 1.225gV newtons
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Weight of Helium = Volume of Helium * Density of Helium * g
W[h] = 0.18gV N
Net Upward force produced by helium, F = Upthrust - Weight = (1.225-0.18) gV = 1.045gV N -----
Weight of 260kg = 2549.7 N
Then to lift the whole thing, F > 2549.7
So minimal F would be 2549.7
----
1.045gV = 2549.7
V = 248.8 m^3
Mass of helium required = V * Density of Helium = 248.8 * 0.18 = 44.8kg (3sf)
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Let the density of the surroundings be R
Then U-W = (1-0.9)RgV = 0.1RgV
So 0.1RgV = 2549.7 N
V = 2549.7 / 0.1Rg
Assuming that R is again 1.255, V = 2071.7 m^3
Then mass of hot air required = 230.2 * 0.9R = 2340 kg
Notice from this that M = 2549.7/0.9Rg * 0.1R so
M[min] = Weight of basket * (difference in density between balloon's gas and surroundings / density of gas in balloon)
M[min] = M[basket] * ΔR/R[b]
The value of cos θ in the given figure is 0.98.
<h3>
What is cosine of an angle?</h3>
The cosine of an angle is defined as the sine of the complementary angle.
The complementary angle equals the given angle subtracted from a right angle, 90.
cos θ = sin(90 - θ)
For example, if the angle is 30°, then its complement is 60°
cos 30 = sin(90 - 30)
cos 30 = sin 60
0.866 = 0.866
<h3>Cosine of an angle with respect to sides of a right triangle</h3>
cos θ = adjacent side / hypotenuse side
adjacent side of the given right triangle is calculated as follows;
adj² = 10² - 2²
adj² = 100 - 4
adj² = 96
adj = √96
adj = 9.8
cos θ = 9.8/10
cos θ = 0.98
Thus, the value of cos θ in the given figure is 0.98.
Learn more about cosine of angles here: brainly.com/question/23720007
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The focal point of a concave mirror is halfway along the radius, therefore the radius would be 2•16= 32 cm
<u><em>It's called geothermal energy, and is present due to the incredible amount of heat present in Earth's interior from radioactive decay, friction, and residual heat from Earth's formation.</em></u>
