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GalinKa [24]
3 years ago
13

A roller coaster car is released from rest as shown in the image below. If

Physics
1 answer:
mrs_skeptik [129]3 years ago
4 0

Answer:

40m/s

Explanation:

a=g

u=0

s=81

v²=u²+2as

v²=2(9.81)(81)

v=√1587.6=39.8446985181≈40m/s

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Simple machines are widely used in our daily life. why?<br>​
HACTEHA [7]

Answer:

Simple machines are useful because they reduce effort or extend the ability of people to perform tasks beyond their normal capabilities. Simple machines that are widely used include the wheel and axle, pulley, inclined plane, screw, wedge and lever.

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3 years ago
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MODERN PHYSICS
frosja888 [35]

Answer:

D. n=6 to n=2

Explanation:

Given;

energy of emitted photon, E = 3.02 electron volts

The energy levels of a Hydrogen atom is given as;  E = -E₀ /n²

where;

E₀ is the energy level of an electron in ground state =  -13.6 eV

n is the energy level

From the equation above make n, the subject of the formula;

n² = -E₀ / E

n² = 13.6 eV / 3.02 eV

n² = 4.5

n = √4.5

n = 2

When electron moves from higher energy level to a lower energy level it emits photons;

E = E_0(\frac{1}{n_1^2}-\frac{1}{n_2^2} )\\\\\frac{1}{n_1^2}-\frac{1}{n_2^2} = \frac{E}{E_o} \\\\\frac{1}{4} -\frac{1}{n_2^2} = \frac{3.02}{13.6} \\\\\frac{1}{4} -\frac{1}{n_2^2} =0.222\\\\\frac{1}{n_2^2} = 0.25 - 0.22\\\\\frac{1}{n_2^2} = 0.03\\\\n_2^2 = 33.33\\\\n_2 = \sqrt{33.33} = 6

For a photon to be emitted, electron must move from higher energy level to a lower energy level. The higher energy level is 6 while the lower energy level is 2

Therefore,  The electron energy-level transition is from n = 6 to n = 2

3 0
3 years ago
1. This image shows the various forces acting on a block of rock situated on a rock slope. What does arrow 4 represent?
Gelneren [198K]

Answer:

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In this problem, the arrow labelled with 4 is the only force pointing downward: therefore, it must be the gravitational force.

The other arrows represent:

1 --> component of the gravitational force parallel to the plane

2 --> force of friction

3 --> component of the gravitational force perpendicular to the plane

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3 years ago
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Out of that list, the concave mirror is the only item that can concentrate sunlight and heat into a small area. But if you could get ahold of a convex lens, that would be even better.
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Answer:

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- The displacement is zero, because the final point corresponds to the initial point

3 0
3 years ago
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