Answer: 18.81m/s^2
Explanation:
Given the following :
Height of building = 0. 1 km = 100m
Horizontal distance = 85m
Using the equation :
S = 1/2gt^2
And S = 100, g = 9.8m/s^2
100 = 0.5(9.8)(t^2)
100 = 4.9(t^2)
t^2 = (100 / 4.9)
t^2 = 20.408
t = 4.5175214
t = 4.52s
Therefore, initial velocity of ball in horizontal direction;
Using the equation:
S = ut + 0.5at^2
a in horizontal direction = 0
Therefore,
S = ut
85 = u × 4.52
u = (85 / 4.52)
u = 18.805
u = 18.81m/s
Explanation:
We see objects in a dark room due to the emission of light photons which are sensitive to our eyes.
Darkness is simply a terminology used to describe the absence of light. Visible light to human is a component of the electromagnetic spectrum. Our eyes have receptors that picks the photons which light releases.
The particles of light are called photons.
- When a torch is shines. It produces light due to emission of light by excitation of the metal in the bulb.
- The light is in form of photons that spreads and travels in all direction in a room.
- When they impinge on other bodies, they cause them to excite and release their own photons
- Photons from the different parts helps to depict an object as it is.
- The photo-receptors in our eyes picks up the photon and interprets it in our visual faculty.
learn more:
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Two factors effecting the magnitude of the force of gravity between 2 objects are the masses and the distance
Explanation:
The magnitude of the gravitational force between two bodies is given by
where
:
is the gravitational constant
are the masses of the two bodies
r is the distance between them
We see therefore that the factors affecting the magnitude of the force of gravity between 2 objects are:
- The mass of the two objects. In particular, the force is proportional to the product of the masses - so the larger the masses, the stronger the force
- The distance between the two objects. In particular, the force is inversely proportional to the square of the distance between the objects - so the larger the distance, the weaker the force
Learn more about gravitational force:
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Answer:
56 N
Explanation:
There are only two forces acting on the package:
- The force of gravity, directed downward, equal to
where m is the mass of the package and g is the acceleration due to gravity
- The air resistance, acting upward, let's label it with
According to Newton's second law, the resultant of the two forces must be equal to the product between the mass, m, and the acceleration, a:
where we have:
m = 20.0 kg
g = 9.8 m/s^2
a = 7.0 m/s^2 is the acceleration when the package is at 25 m above the ground.
Substituting into the equation, we can find the magnitude of the air resistance at that altitude:
There's a very subtle thing going on here, one that could blow your mind.
Wherever we look in the universe, no matter what direction we look,
we see the light from distant galaxies arriving at our telescopes with
longer wavelengths than the light SHOULD have.
The only way we know of right now that can cause light waves to get
longer after they leave the source is motion of the source away from
the observer. The lengthening of the waves on account of that motion
is called the Doppler effect. (The answer to the question is choice-c.)
But that may not be the only way that light waves can get stretched. It's
the only way we know of so far, and so we say that the distant galaxies
are all moving away from us.
From that, we say the whole universe is expanding, and that right there is
one of the strongest observations that we explain with the Big Bang theory
of creation.
Now: If ... say tomorrow ... a competent Physicist discovers another way
for light waves to get stretched after they leave the source, then the whole
"expanding universe" idea is out the window, and probably the Big Bang
theory along with it !
Now that our mind has been blown, come back down to Earth with me,
and I'll give you something else to think about:
It's true that when we look at distant galaxies, we do see their light
arriving in our telescopes with longer wavelengths than it should have.
And then we use the Doppler effect to calculate how fast that galaxy
is moving away from us. That's all true. Astronomers are doing it
every day. I mean every night.
So here's the question for you to think about ... maybe even READ about:
When the light from a distant galaxy pours into our telescope, and we
look at it, and we measure its wavelength, and we find that the wavelength
is longer than it should be ... how do we know what it should be ? ? ?