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Butoxors [25]
3 years ago
7

A 20-kg child running at 1.4 m/s jumps onto a playground merry-go-round that has mass 180 kg and radius 1.6m. She is moving tang

ent to the platform when she jumps and she lands right on the edge. What is the angular velocity of the child and the merry-go-round if the merry-go-round started from rest
Physics
1 answer:
Dominik [7]3 years ago
4 0

Answer:

ωf = 0.16 rad/s

Explanation:

Moment of inertia of the child = mr² = 20(1.6²) = 51.2 kg•m²

Moment of Inertia of the MGR = ½mr² = ½(180)1.6² = 230.4 kg•m²

(ASSUMING it is a uniform disk)

Initial angular momentum of the child = Iω = I(v/r) = 51.2(1.4/1.6) = 44.8 kg•m²/s

Conservation of angular momentum

44.8 = (51.2 + 230.4)ωf

ωf = 0.15909090...

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The magnitude of the Poynting vector of a planar electromagnetic wave has an average value of 0.724 W/m2. What is the maximum va
Hitman42 [59]

Answer:

7.78x10^-8T

Explanation:

The Pointing Vector S is

S = (1/μ0) E × B

at any instant, where S, E, and B are vectors. Since E and B are always perpendicular in an EM wave,

S = (1/μ0) E B

where S, E and B are magnitudes. The average value of the Pointing Vector is

<S> = [1/(2 μ0)] E0 B0

where E0 and B0 are amplitudes. (This can be derived by finding the rms value of a sinusoidal wave over an integer number of wavelengths.)

Also at any instant,

E = c B

where E and B are magnitudes, so it must also be true at the instant of peak values

E0 = c B0

Substituting for E0,

<S> = [1/(2 μ0)] (c B0) B0 = [c/(2 μ0)] (B0)²

Solve for B0.

Bo = √ (0.724x2x4πx10^-7/ 3 x10^8)

= 7.79 x10 ^-8 T

5 0
3 years ago
How does the Earth's rotation affect our view of stars?
rodikova [14]

you only see the stars once every twenty for hours so you can have daylight so because of Earth's rotation you only see the stars for a certain amount of hours

Explanation:

the Earth makes a full rotation so that's why my answer is what it is

5 0
3 years ago
A parallel network consist of three resistors 4 ohm, 8 ohm and 16 ohm .If the current in 8 ohm resistor is 3 A then what are the
Studentka2010 [4]

Answer:

If the resistors are in parallel they must all experience the same voltage drop.

R * I = V

8 * 3 = 24 V    (if i is 3 amps)

24V / 4 ohm = 6 amps

24V / 16 ohm = 1.5 amps

5 0
3 years ago
If the electric field is zero everywhere inside a region of space
Free_Kalibri [48]
My Answer: <span>If the electric field is zero everywhere inside a region of space, the potential must also be zero in that region.</span> If this is a true/false question, the correct answer would be false. 

Hope I helped! :D
5 0
3 years ago
If a football quarterback can throw the ball at 20.0 m/s, what is the furthest distance the quarterback could throw the ball neg
kvasek [131]

The furthest distance the quarterback could throw the ball neglecting air resistance is 81.63 meters.

The situation given above is an example of projectile motion.

The maximum distance up to which a projectile can be thrown is known as its range, which is given by the formula,

Range(R) = 2u^2 sin(2θ)/g

Here u is the maximum velocity of the projectile= 20 m/s

θ is the angle at which the projectile is launched = 45°

g is the acceleration due to gravity = 9.8 m/s^2

Putting the above values in the given equation,

The range comes out to be 81.63 meters.

Hence, the furthest distance the quarterback could throw the ball neglecting air resistance is 81.63 meters.

To know more about "projectile motion", refer to the following link:

brainly.com/question/11422992?referrer=searchResults

#SPJ4

4 0
1 year ago
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