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3 years ago

Which description best explains how a Doppler radar system works?

Physics

1 answer:

Irina-Kira [14]3 years ago

8 0

Answer: A. It reflects waves off of objects, measuring the difference of the waves it sends and receives.

Explanation:

A Doppler radar uses the Doppler effect when measuring return echoes after having sent a signal (in this specific case microwaves).

In this context the Doppler effect consists of the change in a wave perceived frequency when the emitter of the waves, and the receiver (or observer in the case of light) move relative to each other.

In the case of radars, a microwave signal is sent to a target and then reflected, so that the radar system measures this difference between the sent signal and the reflected signal.

It should be noted that this effect bears its name in honor of the Austrian physicist Christian Andreas Doppler, who in 1842 proposed the existence of this effect for the case of light in the stars. Another important aspect is that the effect occurs in all waves (including light and sound). However, it is more noticeable to humans with sound waves.

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Find the length of each vector below.

Leona [35]

Answer:

a. 3.6 units

b. 1.4 units

c. 3.6 units

d. 6.1 units

Explanation:

The length of a vector is given by the following formula:

Length = √(x² + y²)

where,

x = x-component of vector

y = y-component of vector

Here,

x = 2

y = 3

Therefore,

Length = √(2² + 3²)

Length = √13

Length = 3.6 units

Here,

x = 1

y = 1

Therefore,

Length = √(1² + 1²)

Length = √2

Length = 1.4 units

Here,

x = 2

y = -3

Therefore,

Length = √(2² + (-3)²)

Length = √13

Length = 3.6 units

Here,

x = 1

y = -6

Therefore,

Length = √(1² + (-6)²)

Length = √37

Length = 6.1 units

8 0

3 years ago

In a football game, a receiver is standing still, having just caught a pass. Before he can move, a tackler, running at a velocit

Nataliya [291]

Answer:

A) mr = 100 kg

B) Fr = 210N

C) Ft = -199.5N

Explanation:

By conservation of the momentum:

mt*Vo = (mr + mt) * Vf Solving for mr:

mr = mt*Vo / Vf - mt = 100 kg

The average force on the receiver:

mr *(Vf - 0) = Fr * Δt Solving for Fr:

Fr = 210 N

The average force on the tackler:

mt * (Vf - Vo) = Ft * Δt Solving for Ft:

Ft = -199.5 N

8 0

3 years ago

A +8.75 μC point charge is glued down on a horizontal frictionless table. It is tied to a -6.50 μC point charge by a light, nonc

lisov135 [29]

(a) The tension on the wire when the two charges have opposite signs is 383.5 N.

(b) The tension on the wire if both charges were negative is 3.640.25 N.

The given parameters;

first charge, q₁ = 8.75 μC
second charge, q₂ = -6.5 μC
electric field, E = 1.85 x 10⁸ N/C
distance between the two charges, r = 2.5 cm

(a)

The attractive force between the charges is calculated as follows;

$F_1 = \frac{kq_1q_2}{r^2} \\\\F_1 = \frac{(9\times 10^9) \times (8.75\times 10^{-6})\times (-6.5\times 10^{-6})}{(0.025)^2} \\\\F_1 = -819 \ N$

The force on the negative charge due to the electric field is calculated as follows;

$F_2 = Eq_2\\\\F_2 = (1.85 \times 10^8) \times (6.5 \times 10^{-6})\\\\F_2 = 1202.5 \ N$

The tension on the wire is the resultant of the two forces and it is calculated as follows;

$T = F_2 + F_1\\\\T = 1202.5 - 819\\\\T = 383.5 \ N$

(b) when the two charges are negative

The repulsive force between the two charges is calculated as follows;

$F_1 = \frac{kq_1q_2}{r^2} \\\\F_1 = \frac{(9\times 10^9) \times (-8.75\times 10^{-6})\times (-6.5\times 10^{-6})}{(0.025)^2} \\\\F_1 = 819 \ N$

The force on the first negative charge due to the electric field is calculated as follows;

$F_2 = Eq_1\\\\F_2 = (1.85 \times 10^8)\times (8.75 \times 10^{-6})\\\\F_2 = 1618.75 \ N$

The force on the second negative charge due to the electric field is calculated as follows;

$F_3 = Eq_2\\\\F_3 = (1.85 \times 10^8) \times (6.5 \times 10^{-6})\\\\F_3 = 1202.5 \ N$

The tension on the wire is the resultant of the three forces and it is calculated as follows;

$T= F_1 + F_2 + F_3\\\\T= 819 + 1618.75 + 1202.5\\\\T = 3,640.25 \ N$

Learn more here:brainly.com/question/19565286

5 0

3 years ago

What do "Newton's apple" and the moon have in common?

SVEN [57.7K]

Answer:

Both these motions are caused by the Gravitational force of earth.

Explanation:

Both these motions are caused by the Gravitational force of earth.

6 0

3 years ago

Now put that book 5 feet in the air. What kind of energy does the book have? Explain.

erastova [34]

Answer:

Gravitational potential energy

Explanation:

The book is put 5 feet in the air, which means 5 feet above the ground. An object which is located to a certain height above the ground possesses a form of energy called gravitational potential energy, which is the energy due to the fact that the object has "potential" to transform this energy into other forms of energy (e.g. kinetic energy, if the book is released and it starts moving).

The value of the gravitational potential energy of the object is given by the formula:

$U=mgh$

where

m is the mass of the object

g is the gravitational acceleration (9.8 m/s^2)

h is the height of the book above the ground (in this case, 5 feet)

So, we see that the gravitational potential energy is proportional to both the mass and the height of the object.

8 0

4 years ago