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3 years ago

If velocity is decreasing,then acceleration:

1 answer:

5 0

If velocity is decreasing, then acceleration is in the direction
opposite to the velocity.

If the object is moving in the direction that you call 'positive',
then acceleration is negative.

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On what factor does speed of sound depend

velikii [3]

Answer:

For sound waves to travel, there is a requirement of medium and density of the medium is considered to be one of the factors on which the speed of sound depends. When the medium is dense, the molecules in the medium are closely packed which means that the sound travels faster.

Explanation:

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3 years ago

Materials in which electric charges move freely such as copper and aluminum are called

yuradex [85]

Answer:

Conductors allow electric charges to move freely

8 0

3 years ago

An airplane is flying at a speed of 200 m/s in level flight at an altitude of 800 m. A package is to be dropped from the airplan

MArishka [77]

Answer:

2560m or 2.56km (rounded to 3 significant figures)

Explanation:

First, list all known and desired values/variables (initial vertical velocity is 0 as the plane is kept level and vertical acceleration is just gravity):

$Vertical \ velocity \ (\frac{m}{s} ) = u_{v} = 0 \\\\ Horizontal \ velocity \ (\frac{m}{s} ) = u_{h} = 200\\\\ Vertical \ acceleration \ (\frac{m}{s^{2} } ) = a_{v} = 9.8 \\\\ Horizontal \ acceleration \ (\frac{m}{s^{2} } ) = a_{h} = 0 \\\\ Vertical \ displacement \ (m) = s_{v} = 800 \\\\ Horizontal \ displacement \ (m) = s_{h}$

The horizontal displacement is going to be the distance travelled, horizontally of course, once the package is released;

First thing to understand is that the vertical and horizontal components are to be dealt with separately because they don't affect each other;

Since there is no horizontal acceleration (ignoring air resistance), we simply require a velocity and time to find the horizontal displacement, using the formula v = d/t (or speed = distance/time);

What we have is the horizontal velocity but we don't have the time taken;

One thing we know is that the time elapsed for the vertical fall of 800m and for the horizontal displacement must be the same;

What we do, therefore, is find the time taken for the vertical displacement using the formula, s = ut + ¹/₂·at², since we know the vertical velocity, height and acceleration:

800 = (0)t + ¹/₂·(9.8)t²

800 = 4.9t²

t² = 163.26...

t = 12.77...

We now have the time taken for the vertical fall and the horizontal displacement, we can use this with the horizontal velocity we know already and get the horizontal displacement:

$u_{h} = \frac{s_{h} }{t} \\\\ 200 = \frac{s_{h} }{12.77...} \\\\ s_{h} = 200(12.77...) \\\\ s_{h} = 2555.5...$

7 0

3 years ago

Based on the most widely accepted scientific explanation, elements began to form shortly after the big bang. Which of the follow

worty [1.4K]

Big Bang is a theory that, as stated above, has grown to become widely acceptable scientific explanation of the origin of things. Research would say that according to this theory, the Earth originated billion years ago through an explosive of a highly energized point.

Through this explosion, the elements were formed. However, only the lightest of the elements including hydrogen and helium, with traces of lithium and beryllium. From the choices, the answer would have to be the second choice, helium.

Answer: B. helium

5 0

3 years ago

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Which type of graph is best suited to show the breakdown of how this teacher weights each category ?

MArishka [77]

Answer:

pie graph?

Explanation:

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3 years ago

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