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Naddika [18.5K]
2 years ago
5

A 20-kilogram child is riding on a 10-kg sled over a frictionless icy surface at 8.0 meters per second. Calculate the kinetic en

ergy of the sled with the child.
Physics
1 answer:
Veseljchak [2.6K]2 years ago
6 0

Answer:

K = 960 J

Explanation:

Given that,

Mass of a child = 20 kg

Mass of a sled = 10 kg

Speed of child on sled = 8 m/s

We need to find the kinetic energy of the sled with the child.

The total mass of child and the sled = 20 kg + 10 kg

= 30 kg

The formula for the kinetic energy of an object is given by :

K=\dfrac{1}{2}mv^2\\\\K=\dfrac{1}{2}\times 30\times (8)^2\\\\K=960\ J

Hence, the kinetic energy of the sled with the child is 960 J.

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This is simple as power in watts is equal to joules per second so we can do 1500 joules divided by 30 seconds which equals 50 watts
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If a proton were released in the electric field above, what direction would it move?
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Answer:

d because the proton would move towards the negative plate

Explanation:

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3 years ago
A photon of wavelength 192 nm strikes an aluminum surface along a line perpendicular to the surface and releases a photoelectron
alex41 [277]

Answer:

KE=3.529\times10^{−27}\ J

Explanation:

Given that

Wavelength λ=192 nm

So energy of photon,E

E=\dfrac{hC}{\lambda }

Now by putting the values

h=6.6\times 10^{-34}\ m^2.kg/s

C=3\times 10^{8}\ m/s

E=\dfrac{6.6\times 10^{-34}\times 3\times 10^{8}}{192\times 10^{-9} }

E=1.03\times 10^{-18} J

We know that

Kinetic energy given as

KE=\dfrac{P^2}{2m}

KE=\dfrac{E^2}{2mC^2}

KE=\dfrac{(1.03\times 10^{-18})^2}{2\times 1.67\times 10^{-27}(3\times 10^8)^2}

KE=3.529\times10^{−27}\ J

5 0
2 years ago
Two parallel plate capacitors 1 and 2 are identical except that capacitor 1 has charge +q on one plate and charge −q on the othe
Grace [21]

Answer:

a) the capacitance is the same for both capacitors.

b) The potential difference between the plates for the capacitor with charge +2q, is double of the one for the capacitor  with charge +q.

c) The electric field magnitude between the plates for the capacitor with charge +2q, is double of the one for the capacitor with charge +q

d) The energy stored between the plates for the capacitor with charge +2q, is 4 times the value for the one with charge +q  

Explanation:

a) The capacitance of a capacitor, by definition, is as follows:

C = \frac{q}{V}

Appying Gauss' Law to one of plates, it can be showed, that the capacitance (for a parallel plates capacitor) can be  expressed as follows:

C = ε*A / d

As it can be seen, it does not depend on the charge. so we conclude that the capacitance must be the same for both capacitors, due to they are identical except for the value of the charge on the plates.

b) By definition, as we said above, the capacitance is equal to the proportion between the charge of one of the plates, and the potential difference between them.

If this proportion must remain the same, and one of the capacitors has the double of  the charge than the other, the potential difference must be the double also.

c) Applying Gauss' law, to the surface of one of  the plates, and assuming a constant surface charge density σ, it can be  showed that the  electric field can be calculated as follows:

E*A = Q/ε₀ as σ=Q/A

⇒ E = σ/ε₀

As σ is directly proportional to the charge (being the area A the same), we conclude that the electric field for the capacitor with charge +2q must be the double than the one for the capacitior with charge +q.

c) The electric potential energy, stored between plates of a capacitor, can be written as follows:

Ue = \frac{1}{2} *\frac{q^{2}}{C}

If the capacitance remains the same, we can conclude that the electric potential energy for the capacitor with charge +2q, as the charge is raised to the 2nd power, must be 4 times the one for the capacitor with charge +q.

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3 years ago
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avanturin [10]

We can confirm that the difference between a comet and an asteroid lies in their compositions and physical characteristics <u>derived from those compositions</u>.

As stated in the question, the main difference between an asteroid and a comet is their compositions, meaning the materials from which they form.

Asteroids are rocky objects which a heavy metal composition, while comets tend to be made of dust, ice, and <em><u>some </u></em>rocky material. Some extra differences include:

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Therefore, we can confirm that the main difference between asteroids and comets is their compositions, which lead to distinct physical characteristics.

To learn more visit:

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