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2 years ago

Describe three important ways we use the electromagnetic spectrum in our everyday lives.

Physics

1 answer:

OlgaM077 [116]2 years ago

5 0

Answer:

We use X-rays to help the injured, Radiowaves to communicate or entertain, and Visible light to see.

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An airplane propeller is 2.68 m in length (from tip to tip) and has a mass of 107 kg. When the airplane's engine is first starte

telo118 [61]

Answer:

a)30.14 rad/s2

b)43.5 rad/s

c)60633 J

d)42 kW

e)84 kW

Explanation:

If we treat the propeller is a slender rod, then its moments of inertia is

$I =\frac{mL^2}{12} = \frac{107*2.68^2}{12} = 64.04 kgm^2$

a. The angular acceleration is Torque divided by moments of inertia:

$\alpha = \frac{T}{I} = \frac{1930}{64.04} = 30.14 rad/s^2$

b. 5 revolution would be equals to $10\pi$ rad, or 31.4 rad. Since the engine just got started

$\omega^2 = 2\alpha\theta = 2*30.14*31.4 = 1893.5$

$\omega = \sqrt{1893.5} = 43.5 rad/s$

c. Work done during the first 5 revolution would be torque times angular displacement:

$W = T*\theta = 1930 * 31.4 = 60633 J$

d. The time it takes to spin the first 5 revolutions is

$t = \frac{\omega}{\alpha} = \frac{43.5}{30.14} = 1.44 s$

The average power output is work per unit time

$P = \frac{W}{t} = \frac{60633}{1.44} = 41991 W$ or 42 kW

e.The instantaneous power at the instant of 5 rev would be Torque times angular speed at that time:

$P_i = T*\omega = 1930*43.5=83983 W$ or 84 kW

7 0

2 years ago

Correct shape will reduce fluid friction.<br> True <br> False

AURORKA [14]

I believe that is true.

hope this helps!

8 0

2 years ago

Read 2 more answers

Tarzan, in one tree, sees Jane in another tree. He grabs the end of a vine with length 20m that makes an angle of 45° with the v

nadezda [96]

Answer:

yes

Explanation:

3 0

3 years ago

Plane-polarized light is incident on a single polarizing disk, with the direction of E0 parallel to the direction of the transmi

Vladimir [108]

Answer: $65.9^{\circ}$

Explanation:

Given

Intensity must be reduced by a factor of 6

Intensity is given by $I=I_o\cos ^2\theta\\$

Substitute $I$ by $\frac{I_o}{6}$

$\Rightarrow \dfrac{I_o}{6}=I_o\cos ^2\theta\\\\\Rightarrow \cos^2\theta =\dfrac{1}{6}\\\\\Rightarrow \cos \theta=\dfrac{1}{\sqrt{6}}\\\\\Rightarrow \theta=65.9^{\circ}$

So, the disk must be rotated by an angle of $65.9^{\circ}$ .

7 0

2 years ago

What is the net force on charge placed at the center of square of length 1m? All charges have same magnitude of 2 micro coulomb.

Masja [62]

Answer:

Electric Field intensity is zero.

The reason for that is:

All charges are placed at equal distances from the center of the square and have same magnitude and sign. This means they will exert equal and opposite forces on the test charge at the center. Net force will become Zero.

5 0

2 years ago