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3 years ago

Question 11 (3 points)

Physics

1 answer:

kykrilka [37]3 years ago

5 0

Answer:

С. 10.41 Ampere

Explanation:

Given that,

Power, P = 125 watts

Voltage, V = 12 volts

We need to find current. Power in terms of current and voltage is given by :

P = VI, I = current

$I=\dfrac{P}{V}\\\\I=\dfrac{125\ W}{12\ V}\\\\I=10.41\ A$

So, the current is 10.41 A.

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What is the smallest particle that relains<br> the properties of an element

VLD [36.1K]

Answer:

atom

Explanation:

Smallest particle of an element that identifies that element is an atom.

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2 years ago

Two Earth satellites, A and B, each of mass m, are to be launched into circular orbits about Earth's center. Satellite A is to o

Juliette [100K]

(a) 0.473

The potential energy of a satellite orbiting around Earth is given by

$U=-\frac{GMm}{R+h}$

where

G is the gravitational constant

M is the Earth's mass

m is the satellite's mass

R is the Earth's radius

h is the altitude of the satellite above the Earth's surface

So the potential energy of satellite A is

$U_A=-\frac{GMm}{R+h_A}$

while potential energy of satellite B is

$U_B=-\frac{GMm}{R+h_B}$

Therefore the ratio of the potential energy of satellite B to that of satellite A is

$\frac{U_B}{U_A}=\frac{R+h_A}{R+h_B}$

and using

hA = 5920 km

hB = 19600 km

R = 6370 km

we find

$\frac{U_B}{U_A}=\frac{6370+5920}{6370+19600}=0.473$

(b) 0.473

The kinetic energy of a satellite orbiting around Earth instead is given by

$K=\frac{GMm}{2(R+h)}$

So the kinetic energy of satellite A is

$K_A=\frac{GMm}{2(R+h_A)}$

while kinetic energy of satellite B is

$K_B=\frac{GMm}{2(R+h_B)}$

Therefore the ratio of the kinetic energy of satellite B to that of satellite A is

$\frac{K_B}{K_A}=\frac{R+h_A}{R+h_B}$

which is identical to before, so it gives

$\frac{K_B}{K_A}=\frac{6370+5920}{6370+19600}=0.473$

(c) Satellite B

The total energy of a satellite in orbit is given by

$E=U+K = -\frac{GMm}{R+h}+\frac{GMm}{2(R+h)}=-\frac{GMm}{2(R+h)}$

We see that the total energy is:

1) negative (because the satellite is on a bound orbit)

2) inversely proportional to the distance of the satellite from the Earth's center, R+h

So the magnitude of the fraction in the equation is larger for the satellite which is closer to the Earth's surface (satellite A), but since the energy is negative, this means that the total energy of this satellite is smaller than that of satellite B. So, satellite B has a greater total energy.

(d) $1.03\cdot 10^7 J$

We have to calculate the total energy of each satellite.

Given:

$G=6.67\cdot 10^{-11}$

$M=5.98\cdot 10^{24} kg$

m = 12.0 kg

$R+h_A = 6370 km+5920 km=12290 km = 12.3 \cdot 10^6 m$

$R+h_B = 6370 km+19600 km=25970 km = 26.0 \cdot 10^6 m$

We find:

$E_A = - \frac{(6.67\cdot 10^{-11})(5.98\cdot 10^{24})(12.0)}{2(12.3\cdot 10^6)}=-1.95\cdot 10^{7} J$

$E_B = - \frac{(6.67\cdot 10^{-11})(5.98\cdot 10^{24})(12.0)}{2(26.0\cdot 10^6)}=-9.2\cdot 10^{6} J$

So the difference in total energy is

$E_B-E_A = -9.2\cdot 10^6 - (-1.95\cdot 10^7) =1.03\cdot 10^7 J$

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4 years ago

How is Newtons First Law like Inertia?

stellarik [79]

Inertia- a property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force.

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4 years ago

When solid surfaces slide over each other, the kind of friction that occurs is called sliding friction.

LekaFEV [45]

Answer:

True

Explanation:

A sled sliding across snow or ice. Skis sliding against snow. A person sliding down a slide is an example of sliding friction. A coaster sliding against a table. Two cards in a deck sliding against each other. All of these are examples of sliding friction.

Hope this helps! :)

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4 years ago

What are the characteristics of gas giants?

maw [93]

Their compositions are mostly gases, such as hydrogen, and small amountsof rocky material (mostly at theircores). hope this helps .have a nice day

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4 years ago

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