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Vlad1618 [11]
3 years ago
8

HELP. what is the speed of a boat in miles per hour that travels 20 miles in 45 minutes?

Physics
1 answer:
Minchanka [31]3 years ago
6 0

Average speed  =  (distance covered)  /  (time to cover the distance)

                          =          (20 miles)   /   (45 minutes)

Multiply that fraction by  (60 minutes / 1 hour) .
This is equal to ' 1 ', so you won't change anything except the units.

                         =          (20 miles / 45 minutes) times (60 minutes / 1 hour)

Multiply the fractions, then cancel 'minutes' out of
the numerator and denominator.

     =  (20 miles  x  60) / (45  x  1 hour)

     =     (20 x 60 / 45)  miles/hour

     =        26-2/3 miles/hour .  
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The energy of the electron in Hydrogen atom can be shown to be given by En = -13.6/n^2 eV, where n represents the principal quan
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Explanation:

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The energy stored in a wooden log transforms when the log is burned. Which of the following explanations BEST describes how the
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D. the amount of chemical energy equals the amount of heat and light energy.

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Starting from rest, a truck travels in a straight line for 8.0 s with a uniform acceleration of +1.6 m/s2. The driver then appli
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Space vehicles traveling through Earth's radiation belts can intercept a significant number of electrons. The resulting charge b
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Answer:

a) 0.167 μC/m^2

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Explanation:

Hello!

First let's find the surface charge density:

a)

Since thesatellite is metallic, the accumalted charge will be uniformly distribuited on its surface. Therefore the charge density σ will be:

σ = Q/A

Where A is the area of the satellite, which is:

A=4πr^2 = πd^2 = π(1.9m)^2

Therefore:

σ = (1.9)/(π (1.9)^2) μC/m^2 = 0.167 μC/m^2

Now let's calculate the electric field

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Just outside the surface of the satellite the elctric field will be:

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Where      ε0=8.85×10^−12 C/Vm

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E = 1.887 * 10^4 V/m

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