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Katen [24]
3 years ago
13

Police radar guns measure the speed of moving vehicles by transmitting electromagnetic waves at a vehicle and detecting a Dopple

r shift in the reflected wave. Suppose a police radar transmits at a frequency of 26.8 GHz and receives a wave reflected from a car moving toward the radar at 66.0 mph. Find the frequency shift
Physics
1 answer:
Naddika [18.5K]3 years ago
4 0

Answer:

Frequency shift, f = 5270.66

Explanation:

It is given that,

Velocity of the car, v = 66 mph = 29.50 m/s

Frequency transmitted by a police radar, F_s=26.8\ GHz=26.8\times 10^9\ Hz

Frequency shift is given by :

f=\dfrac{2vF_s}{c}

f=\dfrac{2\times 29.50\ m/s\times 26.8\times 10^9\ Hz}{3\times 10^8\ m/s}

f = 5270.66 Hz

So, the frequency shift is 5270.66 hertz. Hence, this is the required solution.

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A very large sheet of insulating material has had an excess of electrons placed on it to a surface charge density of –3.00nC/m2
lys-0071 [83]

Answer: sheet of charge

Explanation:

a )

Since the charge is negative , potential will be negative near it . At a far point potential will be less negative. So potential will virtually increase on going away from the sheet . At infinity it will become almost zero. Electric field will be towards the plate , so potential will decrease towards the plate.

b ) The shape of equi -potential surface will be plane parallel to the sheet of charge because electric field will be perpendicular to the sheet of charge and almost uniform near the sheet of charge.   The equi- potential surface is always perpendicular to electric field.

C ) Electric field which is almost uniform near the sheet of charge is equal t the following

E = σ / ε₀ where  σ is charge density of surface and  ε₀ is permittivity of medium whose value is 8.85 x 10⁻¹²

E = 3 x 10⁻⁹ / 8.85 x 10⁻¹²

= .3389 x 10³

= 338.9 V / m

spacing between 1 V

= 1 / 338.9 m

= 2.95 X 10⁻3 m

= 2.95 mm.

3 0
3 years ago
A 20.0 cm tall object is placed 50.0 cm in front of a convex mirror with a radius of curvature of 34.0 cm. Where will the image
Neko [114]

Answer:

1.Theimage will be located at -0.13m or -13 cm

2.The height of the image will be 0.052m or 5.2cm

Explanation:

Given that;

Height of object, h=20 cm = 0.2m

Object distance in front of convex mirror, o,= 50 cm =0.5m

Radius of curvature, r, =34 cm =0.34m

Let;

Image distance, i,=?

Image height, h'=?

You know that focal length,f, is half the radius of curvature,hence

f=r/2 = 0.34/2 = 0.17m ( this length is inside the mirror, in a virtual side, thus its is negative)

f= -0.17m

Apply the relationship that involves the focal length;

=\frac{1}{o} +\frac{1}{i} =\frac{1}{f}

=\frac{1}{0.5} +\frac{1}{i} =-\frac{1}{0.17}

Re-arrange to get i

\frac{1}{i} =-2-5.88\\\\\\\frac{1}{i} =-7.88\\\\i=-0.13m

This is a virtual image formed at a negative distance produced through extension of drawing rays behind the mirror if you use rays to locate the image behind the mirror

Apply the magnification formula

magnification, m=height of image÷height of object

m=\frac{h'}{h} =-\frac{i}{o}

substitute the values to get the height of image h'

\frac{h'}{0.20} =-\frac{-0.13}{0.5} \\\\\\h'=\frac{0.13*0.20}{0.5} \\\\\\h'=\frac{0.025}{0.5} =0.052m\\\\\\h'=5.2cm

5 0
4 years ago
It's time for Santa to deliver his presents. Assuming he delivers presents all over the world, he has to travel about 75,000,000
algol13
2,419,354.8387960000
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3 years ago
How many meters will a person run during a 5-mile race
Rashid [163]

Answer:

8046.72 meters pretty sure

8 0
3 years ago
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A building contractor says that a certain building foundation should support a pressure greater than 13,000 pa if the area of th
Bess [88]

Answer:

d. 1.69 * 10^6 N

Explanation:

Pressure is defined as force divided by area.

7 0
3 years ago
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