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2 years ago

Worth 50 point!!!

Physics

1 answer:

olasank [31]2 years ago

3 0

Answer:

Chief Hopper

Explanation:

Mike travels at a constant speed of 3.1 m/s. To find how long it takes him to reach the school, we need to find the distance he travels. We can do this using Pythagorean theorem.

a² + b² = c²

(1000 m)² + (900 m)² = c²

c ≈ 1345 m

So the time is:

v = d / t

3.1 m/s = 1345 m / t

t ≈ 434 s

Next, Chief Hopper travels a total distance of 1900 m, starting at rest and accelerating at 0.028 m/s². So we can use constant acceleration equation to find the time.

d = v₀ t + ½ at²

1900 m = (0 m/s) t + ½ (0.028 m/s²) t²

t ≈ 368 s

So Chief Hopper reaches the school first, approximately 66 seconds before Mike does.

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Which of these is true about kinetic energy but not necessarily true about potential energy

cestrela7 [59]

Kinetic energy is never negative, but potential energy can be.

Potential energy depends on height above some reference level,
and you can pick any level you want as the reference. So, if the
object is below the reference level you pick, then its potential
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What that means is: You have to lift it / do work on it / give it more
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(That's exactly the situation with electrons bound to an atom. Their
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give them more energy to rip them away from the atom.)
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Regarding the other choices:

-- Kinetic energy is scalar ... Yes. So is potential energy.

-- Kinetic energy increases with height ...
No. It doesn't, but potential energy does.

-- Kinetic energy depends on position ...
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2 years ago

A radar for tracking aircraft broadcasts a 12 GHz microwave beam from a 2.0-m-diameter circular radar antenna. From a wave persp

NISA [10]

A) 750 m

First of all, let's find the wavelength of the microwave. We have

$f=12GHz=12\cdot 10^9 Hz$ is the frequency

$c=3.0\cdot 10^8 m/s$ is the speed of light

So the wavelength of the beam is

$\lambda=\frac{c}{f}=\frac{3\cdot 10^8 m/s}{12\cdot 10^9 Hz}=0.025 m$

Now we can use the formula of the single-slit diffraction to find the radius of aperture of the beam:

$y=\frac{m\lambda D}{a}$

where

m = 1 since we are interested only in the central fringe

D = 30 km = 30,000 m

a = 2.0 m is the aperture of the antenna (which corresponds to the width of the slit)

Substituting, we find

$y=\frac{(1)(0.025 m)(30000 m)}{2.0 m}=375 m$

and so, the diameter is

$d=2y = 750 m$

B) 0.23 W/m^2

First we calculate the area of the surface of the microwave at a distance of 30 km. Since the diameter of the circle is 750 m, the radius is

$r=\frac{750 m}{2}=375 m$

So the area is

$A=\pi r^2 = \pi (375 m)^2=4.42\cdot 10^5 m^2$

And since the power is

$P=100 kW = 1\cdot 10^5 W$

The average intensity is

$I=\frac{P}{A}=\frac{1\cdot 10^5 W}{4.42\cdot 10^5 m^2}=0.23 W/m^2$

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2 years ago

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1. friction between water molecules
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2 years ago

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prohojiy [21]

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Explanation:

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In this sense, there are different types of friction force thath are useful in different situations:

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Shkiper50 [21]

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Hope this helps! :D

-TanqR

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2 years ago

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