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2 years ago

17 1. Which statement about Kepler's law of harmonies is correct?

Physics

1 answer:

Sindrei [870]2 years ago

5 0

Answer:

Explanation:

Let T be the orbit period and a be the radius of orbit.

For T^2= k× a^3 (k is a constant)

there seems to be an indirect relationship between two variables.

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Janelle wants to buy some strings of decorative lights for her home. She is trying to decide between two strings of lights that

inysia [295]

If she has a choice and the wiring details are stated on the packaging,
then Janelle should look for lights that are wired in parallel within the
string, and she should avoid lights that are wired in series within the string.

If a single light in a parallel string fails, then only that one goes out.
The rest of the lights in the string continue to shimmer and glimmer.

If a single light in a series string fails, then ALL of the lights in that string
go out, and it's a substantial engineering challenge to determine which light
actually failed.

6 0

3 years ago

Read 2 more answers

A 25 kg child stands 2.5 m from the center of a frictionless merry‐go‐round, which has a 200 kg*m^2 moment of inertia and is spi

vodka [1.7K]

Answer:

Explanation:

a ) Time period T = 2 s

Angular velocity ω = 2π / T

= 2π / 2 = 3.14 rad /s

Initial moment of inertia I₁ = 200 + mr²

= 200 + 25 x 2.5²

=356.25

Final moment of inertia

I₂ = 200 + 25 X 1.5 X 1.5

= 256.25

b ) We apply law of conservation of momentum

I₁ X ω₁ = I₂ X ω₂

ω₂ = I₁ X ω₁ / I₂

Putting the values

$w_2=\frac{356.25\times3.14}{256.25}$

ω₂ = 4.365 rad s⁻¹

c ) Increase in rotational kinetic energy

=1/2 I₂ X ω₂² - 1/2 I₁ X ω₁²

.5 X 256.25 X 4.365² - .5 X 356.25 X 3.14²

= 684.95 J

This energy comes from work done against the centripetal pseudo -force.

7 0

3 years ago

A sound wave was determined to have a frequency of 0.3 Hz, speed of 150 cm/s, and amplitude of 2 cm. Find its wavelength.

fredd [130]

Answer:

5 m

Explanation:

From the question,

v = λf....................... Equation 1

Where v = speed of the sound wave, λ = wavelength of the sound wave, f = frequency of the sound wave.

make λ the subject of the equation

λ = v/f..................... Equation 2

Given: v = 150 cm/s = 1.5 m/s, f = 0.3 hz.

Substitute these values into equation 2

λ = 1.5/0.3

λ = 5 m.

7 0

2 years ago

Your friend, who is in a field 100 meters away from you, kicks a ball towards you with an initial velocity of 16 m/s. Assuming t

LekaFEV [45]

Answer:

Time, t = 5.355 seconds

Explanation:

Given the following data;

Distance = 100 m

Initial velocity = 16 m/s

Deceleration = 1 m/s²

To find the time, we would use the second equation of motion;

But since the ball is decelerating, it's acceleration would be negative.

S = ut + ½at²

Where;

S represents the displacement or height measured in meters.

u represents the initial velocity measured in meters per seconds.

t represents the time measured in seconds.

a represents acceleration measured in meters per seconds square.

Substituting into the equation, we have;

100 = 16t - 0.5t²

200 = 32t - t²

t² + 32t - 200 = 0

Solving the quadratic equation using the quadratic formula;

The quadratic equation formula is;

$x = \frac {-b \; \pm \sqrt {b^{2} - 4ac}}{2a}$

Substituting into the equation, we have;

$x = \frac {-32 \; \pm \sqrt {32^{2} - 4*1*(-200)}}{2*1}$

$x = \frac {-32\pm \sqrt {1024 - (-800)}}{2}$

$x = \frac {-32 \pm \sqrt {1024 + 800}}{2}$

$x = \frac {-32 \pm \sqrt {1824}}{2}$

$x = \frac {-32 \pm 42.71}{2}$

$x_{1} = \frac {-32 + 42.71}{2}$

$x_{1} = \frac {10.71}{2}$

x1 = 5.355

We do not need the negative value of x, so we proceed.

Therefore, time = 5.355 seconds

3 0

2 years ago

Which best describes a concave lens?

-Dominant- [34]

Answer:

Explanation:

Concave lens also called as diverging lens i.e. it diverges ray of light coming towards it.

Concave lens is thicker at the edges and thinner at the center.

Concave lens formed the virtual image of the object i.e. it cannot be trace on screen. This lens is used to treat the nearsightedness or myopia in which a person is unable to see the far object clearly.

4 0

3 years ago