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3 years ago

6

Help with Physical Science! I have to do this discussion on potential and kinetic energy. The example of the problem is a 4 poun

d weight being lifted from the ground on a string. There are also scissors there to cut the string for the 4 pound to drop. The two questions is to explain how the object (the weight on the string) had potential energy. And how the object had kinetic energy. THANK YOU

1 answer:

algol [13]3 years ago

8 0

Answer:

Tying a 4 weight pound on a string is a potential energy because it is at rest but cutting it and letting it fall experiences a kinetic energy because it will be in motion.

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What is the displacement of a spring if it has a spring constant of 10 N/m, and a force of 2.5 N is applied?

pochemuha

O.25 m is the displacement

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2 years ago

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In the Hydrogen atom, the energy spacing between the is 4.07 x 101 J (Joules). When an is the frequency of the photons emitted?

agasfer [191]

Answer:

The frequency of the photon is $3.069\times10^{14}\ Hz$ .

Explanation:

Given that,

Energy $E=4.07\times10^{-19}\ J$

We need to calculate the energy

Using relation of energy

$E_{4}-E_{2}=\Delta E$

Where, $\Delta E$ = energy spacing

$4h\nu-2h\nu=4.07\times10^{-19}$

$\nu=\dfrac{4.07\times10^{-19}}{2h}$

Put the value of h into the formula

$\nu=\dfrac{4.07\times10^{-19}}{2\times6.63\times10^{-34}}$

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Hence, The frequency of the photon is $3.069\times10^{14}\ Hz$ .

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2 years ago

What travels by vibrating particles? Mechincal Waves or ElecrtoMagnetic Waves.

Naddik [55]

Answer:mechanical waves.

Explanation:

Mechanical waves require the particles of the medium to vibrate in order for energy to be transferred. For example, water waves, earthquake/seismic waves, sound waves, and the waves that travel down a rope or spring are also mechanical waves.

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2 years ago

A pendulum has a length of 2 m and a 30 kg mass hanging on the end. What is the period of the

anastassius [24]

Answer:

T = 2.83701481512 seconds

Explanation:

Hi!

The formula that you will want to use to solve this question is:

$T = 2\pi *\sqrt{\frac{L}{g} }$

T--> period

L --> length of the pendulum

g --> acceleration due to gravity (9.8m/s^2)

since we know that the mass of the bob at the end of the pendulum does not affect the period of the pendulum, we can go ahead and ignore that bit of information (unless, of course, the weight causes the pendulum to stretch)

so now we can plug in our given info into the formula above and solve!

T = 2*pi * sqrt(2/9.8)

T = 2.83701481512 seconds

*Note*

- I used 3.14 to pi, if you need to use a different value for pi (a longer version, etc) your answer will be slightly different

I hope this helped!

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2 years ago

An insulated rigid tank contains 3 kg of H2O in the form of a saturated mixture of liquid and vapor at a pressure of 150 kPa and

Andre45 [30]

Answer:

change in entropy is 1.44 kJ/ K

Explanation:

from steam tables

At 150 kPa

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Vf = 0.001053 m^3/kg

vg = 1.1594 m^3/kg

specific entropy values are

Sf = 1.4337 kJ/kg K

Sfg = 5.789 kJ/kg

initial specific volume is calculated as

$v_1 = vf + x(vg - vf)$

$= 0.001053 + 0.25(1.1594 - 0.001053)$

$v_1 = 0.20964 m^3/kg$

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FROM STEAM Table

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Vf = 0.001061 m^3/kg

vg = 0.88578 m^3/kg

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constant volume so $v_1 - v_2 = 0.29064 m^3/kg$

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$x_2 = 0.327$

$s_2 = 1.5302 + 0.32 \times 5.5968 = 3.36035 kJ/kg K$

Change in entropy $\Delta s = m(s_2 - s_1)$

=3( 3.36035 - 2.88) = 1.44 kJ/kg

8 0

3 years ago