A bird has a mass of 0.8 kg and flies at a speed of 11.2 m/s. How much kinetic energy does the bird have?
2 answers:
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Answer:
I = W / 4π R_{s}², P = W / 2π c R_{s}², Io /I_{earth} = 10⁴
Explanation:
The intensity is defined as the ratio between the emitted power and the area of the spherical surface
I = P / A
Since the emitted power is constant and has a value of W for this case, let's look for the area of the sphere on the surface of the sun
A = 4π ²
I = W / 4π R_{s}²
.- The radiation pressure for total absorption is
P = S / c
Where S is the Pointer vector that is equal to the intensity
Let's replace
P = W / 2π c R_{s}²
.- We repeat for r = R_{s}/2
I₂ = W / 4π (R_{s}/ 2)²
I₂ = 4 W / 4π R_{s}²
I₂ = 4 Io
I₀ = W / 4piRs2
We calculate the radiation pressure
P₂ = I₂ / c
P₂ = 4 I₀ / c
P₂ = 4 (W / 4pi c Rs2)
.- the relationship between these magnitudes is
I₂ / I₀ = 4
P₂ / P₀ = 4
Let's calculate the intensity on the surface where the Earth is
r = 1.50 10¹¹ m
= W / 4π r²
Io / I_{earth} = r² /²
Io /I_{earth} = (1.5 10¹¹ / 6.96 10⁸) 2
Io /I_{earth} = 4.6 10⁴
Io /I_{earth} = 10⁴
Answer:
Terminal voltage = 11.5 V
Power across load = 119.7 W
Power across internal resistance = 5.4 W
Power delivered by battery = 125.2 W
Explanation:
The current in the circuit is given by
where E is the emf of the battery, R us the load resistance and r is the internal resistance.
The terminal voltage is the potential difference across the load resistor.
V = I × R = 10.43 A × 1.1 Ω = 11.5 V
The power across any resistance is given by
For the load resistor,
For the internal resistance,
The power delivered by the battery is
This could also be found by
The discrepancy in both answers is due to the approximations. The second answer is better.
<u>Answer:</u>
1) Distance traveled by bird = 403 meter
2)Average speed = 1.66 km /hour
3) Zcceleration = 2
<u>Explanation:</u>
1) Distance traveled = Speed * Time taken = 31 * 13 = 403 meter.
2) Average speed = Total distance covered / Time taken for that distance to cover.
Total distance covered = 2+0.5+2.5 = 5 km
Time taken = 3 hours
Average speed = 5/3 = 1.66 km /hour
3) Acceleration is defined as the rate of change of velocity, so acceleration a = change in velocity/time.
Change in velocity = 14 - 6 = 8 m/s
Time = 4 seconds
So acceleration = 8 / 4 = 2