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Papessa [141]
3 years ago
8

After the first few seconds of a race, a runner runs at the same speed until she approaches the finish line, at which point she

increases her speed. Which statement best explains why she only did work at the beginning and end of the race? (Ignore work done against air resistance and friction.)
Physics
1 answer:
Rzqust [24]3 years ago
5 0

DUJFIOflmC VANWSER

EXPLANTATION

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A low orbit satellite at 100 km altitude had a camera that resolved a car location to within 0.3 meter. Find the minimum diamete
NeX [460]

Answer:

Minimum diameter of the camera lens is 22.4 cm

The focal length of the camera's lens is 300cm

Explanation:

y = Resolve distance = 0.3 m

h = Height of satellite = 100 km

λ = Wavelength = 550 nm

Angular resolution

tan\theta\approx \theta =\frac{y}{h}\\\Rightarrow \theta=\frac{0.3}{100\times 10^3}=3\times 10^{-6}

From Rayleigh criteria

sin\theta=1.22\frac{\lambda}{D}\\\Rightarrow D=1.22\frac{\lambda}{sin\theta}\\\Rightarrow D=1.22\frac{550\times 10^{-9}}{sin3\times 10^{-6}}=0.2236\ m=22.4\ cm

Minimum diameter of the camera lens is 22.4 cm

Relation between resolvable feature, focal length and angular resolution

d=f\Delta \theta\\\Rightarrow f=\frac{d}{\Delta \theta}\\\Rightarrow f=\frac{9\times 10^{-6}}{3\times 10^{-6}}=3\ m=300\ cm

The focal length of the camera's lens is 300cm

3 0
3 years ago
Number 13 please!!!!!!!!!!!
atroni [7]
'A' and 'C' both show that behavior.

'D' also shows it, but the object is moving backwards when time begins.
First it moves faster and faster backwards, then it moves slower and slower backwards.
4 0
3 years ago
What was the greatest discovery by galileo during his inclined-plane experiments?
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Galileo discovered during his inclined-plane experiments that a ball rolling down an incline and onto a horizontal surface would roll indefinitely.
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5. A cart with one fan on It blowing to the left and carrying one block produces the x vs t graph shown If this car were carryin
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Answer:

Graph C

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A __ is used to measure air pressure.
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A barometer is used to measure air pressure!
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