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2 years ago

Which phrase describes an electromagnetic wave

Physics

1 answer:

Viefleur [7K]2 years ago

4 0

Answer:

a transverse wave consisting of changing electric fields and changing magnetic fields.

Explanation:

An electromagnetic wave is a wave generated by the vibration of perpendicular electric and magnetic fields, which may progate through vacuum (empty space) or a material medium.

All electromagnetic waves propagate at the same speed in vacuum. This speed is approximately 3.0 × 10⁸ m/s. Which is generally referred as the speed of light, but it is the same constant speed of any electromagnetic wave in the vacuum, c.

In general, waves transfer energy when they travel, but only electromagnetic waves can travel in vacuum. The waves that cannot travel in vacuum are named mechanical waves (they need a medium to travel).

There are two types of waves depending on how they propagate: transverse waves and longitudinal waves. The transverse waves travel perperdiculary to the direcction of the vibration, while longitudinal waves travel parallel to the direction of the vibration.

The classical example of transverse waves is a rope that oscilates up and down. The classical example of longitudinal waves is a spring that you pull and push by an end and so it moves forward and back. Sound is also a longitudinal wave.

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Sarah and Kenneth are going to meet partway between their homes and each leave their home at the same time. Sarah drives at 31.0

valentina_108 [34]

Answer:

b) 105220.8 m

c) 65.38 miles

d) Kenneth's home

Explanation:

Velocity of Sarah = 31 m/s east

Velocity of Kenneth = 65 mph = 65×(1609.34/3600) m/s west

Time in seconds = 29.2×60 = 1752 s

Displacement = Velocity × time

Displacement of Sarah = 31×1752 = 54312 m

Displacement of Kenneth = 65×(1609.34/3600)×1752 = 50908.8 m

b) So, distance between their homes in meters is 54312 m + 50908.8 m = 105220.8 m

c) Converting to miles

$\frac{105220.8}{1609.34}=65.38\ miles$

Their homes are 65.38 miles apart

d) They met closer to Kenneth's house (50908.8 m)

6 0

3 years ago

A bullet of inertia m traveling at speed v is fired into a wooden block that has inertia 4m and rests on a level surface. The bu

GREYUIT [131]

Answer:

F = mv²/(18d)

Explanation:

Momentum before collision = momentum after collision

mv = m(v/3) + (4m) V

v = v/3 + 4V

4V = 2v/3

V = v/6

The acceleration of the block is:

v² = v₀² + 2aΔx

(0 m/s)² = (v/6)² + 2ad

2ad = -v²/36

a = -v²/(72d)

The friction force is therefore:

∑F = ma

-F = (4m) (-v²/(72d))

F = mv²/(18d)

The energy dissipated during the collision is:

ΔE = 1/2 mv² − (1/2 m(v/3)² + 1/2 (4m)(v/6)²)

ΔE = 1/2 mv² − (1/18 mv² + 1/18 mv²)

ΔE = 1/2 mv² − 1/9 mv²

ΔE = 7/18 mv²

The energy dissipated by the friction force:

W = Fd

W = 1/18 mv²

The ratio is:

ΔE / W

(7/18 mv²) / (1/18 mv²)

5 0

3 years ago

How does the energy used by a 100 W lightbulb compare with the energy used by a 40 W lightbulb in a given amount of time? The 10

MatroZZZ [7]

The correct answer is
The 100 W bulb uses 2.5 times more energy

In fact, the power is the amount of energy used per unit of time. This means that the light bulb of 100 W uses 100 J in one second, and the light bulb of 40 W uses 40 J in one second, and if we compare the two numbers, we get
 $\frac{100 J}{40 J}=2.5$
so, the 100 W light bulb uses 2.5 times more energy than the 40 W light bulb.

7 0

3 years ago

Read 2 more answers

Dario, a prep cook at an Italian restaurant, spins a salad spinner and observes that it rotates 20.0 times in 5.00 seconds and t

mamaluj [8]

Answer:

8.37758 rad/s²

Explanation:

$\omega_i$ = Initial angular velocity = $20\times \frac{2\pi}{5}$

$\omega_f$ = Final angular velocity = 0

$\theta$ = Angle of rotation = $6\times 2\pi\ rad$

Equation of rotational motion

$\omega_f^2-\omega_i^2=2\alpha \theta\\\Rightarrow \alpha=\frac{\omega_f^2-\omega_i^2}{2\theta}\\\Rightarrow \alpha=\frac{0^2-(20\times \frac{2\pi}{5})^2}{2\times 6\times 2\pi}\\\Rightarrow \alpha=-8.37758\ rad/s^2$