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3 years ago

Which statement demonstrates that ultraviolet (UV) rays are electromagnetic waves?

Physics

2 answers:

MA_775_DIABLO [31]3 years ago

5 0

The answer is B) They do NOT require a medium to travel.

aalyn [17]3 years ago

4 0

B. They don't require a medium to travel

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The skateboarder starts at the top of the ramps, and rolls down and back up the other side. Which graph shows the most Kinetic E

DaniilM [7]

Answer:

Explanation:

Usually when you are at the bottom you are at peak speed. It also shows that Kinetic Energy is the green bar and in picture C the green bar is highest.

6 0

2 years ago

A hollow conductor is positively charged. Asmall uncharged metal ball is lowered by a silk thread through asmall opening in the

dimulka [17.4K]

Answer:

Explanation:

According to the property of a conductor, the entire charge will reside on the outer surface of the conductor, there is no charge on the inner side of the conductor. As the uncharged metal ball touches the inner surface of the conductor, it does not attain any charge as the inner side of the conductor has no charge.

So option (c) is correct.

8 0

3 years ago

A small airplane with a wingspan of 18.0 m is flying due north at a speed of 63.6 m/s over a region where the vertical component

choli [55]

Answer:

(a) ε = 1373.8.

(b) The wingtip which is at higher potential.

Explanation:

(a) Finding the potential difference between the airplane wingtips.

Given the parameters

wingspan of the plane is = 18.0m

speed of the plane in north direction is = 70.0m/s

magnetic field of the earth is = 1.20μT

The potential difference is given as:

ε = Blv

where ε = potential difference of wingtips

B = magnetic field of earth

l = wingspan of airplane

v = speed of airplane

ε = 1.2 x 18.0 x 63.6

ε = 1373.8

(b) Which wingtip is at higher potential?

The wingtip which is at higher potential.

5 0

3 years ago

An 80.0-kg object is falling and experiences a drag force due to air resistance. The magnitude of this drag force depends on its

Zinaida [17]

Answer:

Terminal velocity of object = 12.58 m/s

Explanation:

We know that the terminal velocity is attained when drag force and gravitational force are of the same magnitude.

Gravitational force = mg = 80 * 9.8 = 784 N

Drag force = $12.0v+4.00v^2$

Equating both, we have

$784=12.0v+4.00v^2\\ \\ v^2+3v-196=0\\ \\ (v-12.58)(v+15.58)=0$

So v = 12.58 m/s or v = -15.58 m/s ( not possible)

So terminal velocity of object = 12.58 m/s

3 0

3 years ago

A lamp in a child's Halloween costume flashes based on an RC discharge of a capacitor through its resistance. The effective dura

pshichka [43]

Answer:

A. 0.199 J

B. 0.0663 C

C = 0.0221 F

D. 12.68 ohms

Explanation:

From the question:

time duration, t = 0.28 seconds

Average power, P = 0.71 W

Average voltage, V = 3 V

A) Energy is given as:

E = P * t

=> E = 0.71 * 0.28 = 0.199 J

B) Electrical energy is also given as:

E = qV

where q = charge

=> q = E / V

∴ q = 0.199 / 3 = 0.0663 C

C) Capacitance is given as charge over voltage:

C = q / V

=> C = 0.0663 / 3 = 0.0221 F

D) Electrical power, P, can also be given as:

P = $V^2 / R$

where R = resistance

=> R = $V^2 / P$

R = $3^2 / 0.71 = 9 / 0.71 = 12.68 ohms$

8 0

3 years ago