Answer:
a. 2865 km
Explanation:
Eratosthenes observed that the sun's rays formed a vertical angle of 7º 12 ’. Which confirmed that the Earth was not flat, assuming that it had a spherical shape, using the distance between Alexandria and Siena and the measure of the angle of inclination of the solar rays in Alexandria, calculated the circumference of the Earth.
The calculation was made with a simple rule of three:
angle of inclination of the solar rays——————- distance
360º ————- Planet circumference
And since we know that:
Answer:
The state of being free from the effects of gravity.
Answer:
2577 K
Explanation:
Power radiated , P = σεAT⁴ where σ = Stefan-Boltzmann constant = 5.6704 × 10⁻⁸ W/m²K⁴, ε = emissivity of bulb filament = 0.8, A = surface area of bulb = 30 mm² = 30 × 10⁻⁶ m² and T = operating temperature of filament.
So, T = ⁴√(P/σεA)
Since P = 60 W, we substitute the vales of the variables into T. So,
T = ⁴√(P/σεA)
= ⁴√(60 W/(5.6704 × 10⁻⁸ W/m²K⁴ × 0.8 × 30 × 10⁻⁶ m²)
= ⁴√(60 W/(136.0896 × 10⁻¹⁴ W/K⁴)
= ⁴√(60 W/(13608.96 × 10⁻¹⁶ W/K⁴)
= ⁴√(0.00441 × 10¹⁶K⁴)
= 0.2577 × 10⁴ K
= 2577 K
The final speed of C is equal to that of B.
The travel time of A is less than that of B.
The final speed of B is equal to that of A.
The travel time of C is greater than that of B.
The final speed of A is equal to that of C.
The travel time of C is greater than that of A.
<h3>What is speed?</h3>
The speed of any moving object is the ratio of the distance covered and the time taken to cover that distance.
Consider the three inclines shown in the figure (attached below). The vertical line is an incline with a 90° angle. All three inclines are frictionless. Three small identical objects are released from the top of the inclines.
When the objects are at the same height, they travel with the same height. The travel time is directly proportional to the incline.
Thus, all the statements are completed.
Learn more about speed.
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