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aliya0001 [1]
3 years ago
6

Radar is used to determine distances to various objects by measuring the round-trip time for an echo from the object. (a) How fa

r away is the planet Venus if the echo time is 1000 s? (b) What is the echo time for a car 75.0 m from a Highway Police radar unit?
Physics
1 answer:
BartSMP [9]3 years ago
8 0

Answer

given,

Echo time = t = 1000 s

speed = ?

v = \dfrac{d}{t}

a) speed of electromagnetic wave

c = \dfrac{d}{t}

wave travels Venus two time

c = \dfrac{2d}{t}

d = \dfrac{ct}{2}

d = \dfrac{3 \times 10^8\times 1000}{2}

d = 1.5 x 10¹¹ m

b) now, echo time

    c = \dfrac{2d}{t}

    t = \dfrac{2d}{c}

    t = \dfrac{2\times 75}{3 \times 10^8}

          t = 5 x 10⁻⁷ s

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Answer:

-0.038 N

Explanation:

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F= 9×10^9×1×10^-5×-1.5×10^-5/(6)^2

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2 years ago
If the mass of a person is 600kg on Earth what is the persons mass on the moon
nika2105 [10]

Answer:

The mass of the person would remain 600kg.

Explanation:

mass refers to the amount of matter in a particular object. therefore even though the moon has less gravitational force than the Earths, it still would have the same mass since the person is made up of the same amount of matter on Earth and in the moon.

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3 years ago
A parallel-plate capacitor with plates of area 600 cm^2 is charged to a potential difference V and is then disconnected from the
Julli [10]

Answer:

<h2>a) Q = 0.759µC</h2><h2>b) E = 39.5µJ</h2>

Explanation:

a) The charge Q on the positive charge capacitor can be gotten using the formula Q = CV

C = capacitance of the capacitor (in Farads )

V = voltage (in volts) = 100V

C = ∈A/d

∈ = permittivity of free space = 8.85 × 10^-12 F/m

A = cross sectional area = 600 cm²

d= distance between the plates = 0.7cm

C = 8.85 × 10^-12 * 600/0.7

C = 7.59*10^-9Farads

Q = 7.59*10^-9 * 100

Q = 7.59*10^-7Coulombs

Q = 0.759*10^-6C

Q = 0.759µC

b) Energy stored in a capacitor is expressed as E = 1/2CV²

E = 1/2 * 7.59*10^-9 * 100²

E = 0.0000395Joules

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7 0
2 years ago
The efficiency of a device such as a lamp can be calculated using this equation:
loris [4]

efficiency = (useful energy transferred ÷ energy supplied) × 100

It's easy to use this formula, but we have to know both the useful energy and the energy supplied.  The drawing doesn't tell us the useful energy, so we have to find a clever way to figure it out.  I see two ways to do it:

<u>Way #1:</u>

We all know about the law of conservation of energy.  So we know that the total energy coming out must be  250J, because that's how much energy is going in.  The wasted energy is 75J, so the rest of the 250J must be the useful energy . . . (250J - 75J) = 175J useful energy.

(useful energy) / (energy supplied) =  (175J) / (250J) = <em>70% efficiency</em>

================================

<u>Way #2: </u>

How much of the energy is wasted ? . . . 75J wasted

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30% of the input energy is wasted.  That leaves the other <em>70%</em> to be useful energy.

6 0
2 years ago
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Discuss the limitations of using the Doppler shift to determine an object's speed.
pantera1 [17]

Answer and Explanation:

Limitation of Doppler shift :

The Doppler impact is relevant when the speeds of the wellspring of sound and spectator are considerably less than the speed of sound. The movement of both the spectator and the source is along a similar straight line.When movement is not in straight line or velocity is not much less than speed of light then we can not use Doppler shift

This is the limitation of Doppler shift to determine the object distance

3 0
3 years ago
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