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2 years ago

15

A satellite phone can be used to place a call from virtually anywhere in the world. What type of wave does the satellite phone l

ikely transmit to the satellite orbiting above Earth?
sound wave

visible light

gamma ray

radio wave

2 answers:

SIZIF [17.4K]2 years ago

7 0

Radio wave because the others are wrong

Strike441 [17]2 years ago

6 0

Gamma ray because I believe it makes sense

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What occurs any time an object speeds up, slows down, or changes directions

Svetlanka [38]

Whenever the motion of an object <em><u>changes</u></em> . . . speeding up, or slowing down,
or changing direction . . . that change is called "<em><u>acceleration</u></em>". Acceleration is
produced by force on the object.

If there is <em><u>no force</u></em> on the object, then there is no acceleration. That means that
its motion <em><u>doesn't change</u></em>. The object remains in constant, uniform motion ...
moving with steady speed, in a straight line.

No force is necessary to <em><u>keep</u></em> an object moving, only to <em><u>change</u></em> its motion.

4 0

3 years ago

A horizontal circular platform (m = 119.1 kg, r = 3.23m) rotates about a frictionless vertical axle. A student (m = 54.3kg) walk

Murrr4er [49]

Answer:

$\omega_2=5.1rad/s$

Explanation:

Since there is no friction angular momentum is conserved. The formula for angular momentum thet will be useful in this case is $L=I\omega$ . If we call 1 the situation when the student is at the rim and 2 the situation when the student is at $r_2=1.39m$ from the center, then we have:

$L_1=L_2$

Or:

$I_1\omega_1=I_2\omega_2$

And we want to calculate:

$\omega_2=\frac{I_1\omega_1}{I_2}$

The total moment of inertia will be the sum of the moment of intertia of the disk of mass $m_D=119.1 kg$ and radius $r_D=3.23m$ , which is $I_D=\frac{m_Dr_D^2}{2}$ , and the moment of intertia of the student of mass $m_S=54.3kg$ at position $r$ (which will be $r_1=r=3.23m$ or $r_2=1.39m$ ) will be $I_{S}=m_Sr_S^2$ , so we will have:

$\omega_2=\frac{(I_D+I_{S1})\omega_1}{(I_D+I_{S2})}$

or:

$\omega_2=\frac{(\frac{m_Dr_D^2}{2}+m_Sr_{S1}^2)\omega_1}{(\frac{m_Dr_D^2}{2}+m_Sr_{S2}^2)}$

which for our values is:

$\omega_2=\frac{(\frac{(119.1kg)(3.23m)^2}{2}+(54.3kg)(3.23m)^2)(3.1rad/s)}{(\frac{(119.1kg)(3.23m)^2}{2}+(54.3kg)(1.39m)^2)}=5.1rad/s$

6 0

3 years ago

Q 6: A body throws a ball vertically up. It returns to the ground after 5 seconds. Find

Rasek [7]

Answer:

Taking gravity to be 9.8m/s2, The velocity is 24.5m/s2.

Taking gravity to be 10m/s2, The velocity is 25m/s2.

Explanation:

According the first formula of motion under the influence of gravity for upward motion, v=u-gt, where v=final velocity, u=initial velocity, and t= time taken.

Here the time taken for the ball to reach the maximum point is half of 5, which is 2.5 seconds.

And v is 0, since at the maximum point gravity slows down the velocity to 0.

Finding the initial velocity,

v=u-gt

0=u-10(2.5)

u=10(2.5)

u=25m/s

8 0

3 years ago

The solubility of a gas is .55 g/l at 8.0 atm pressure. what will be the solubility of the gas at 5.0 atm partial pressure?

garik1379 [7]

Henry's law states that:

P1/C1 = P2/C2

Where P = Pressure, and C = Solubility
In this case, P1 = 8.0 atm, C1 = 0.55 g/l, P2 = 5.0 atm, C2 =??

Therefore,
C2 = (P2*C1)/P1 = (5*0.55)/8 = 0.344 g/l

8 0

3 years ago

The alternating current which crosses an apparatus of 600 W has a maximum value of 2.5 A. What is efficient voltage between its

azamat

Answer: Option (b) is correct.

Explanation:

Since we know that,

P = VI

where;

P = power

V= Voltage

I = Current

Since it's given that,

P = 600W

I = 2.5 A

equating these values in the above equation, we get;

<em>V = $\frac{600}{2.5}$ </em>

<em>V = 240 V</em>

8 0

3 years ago