How often do industrial oxygen cylinders need to be tested

why are waves faster in liquids and gases than in air

Alika [10]

Answer:

Sound travels faster in liquids than in gases because molecules are packed more closely together. This means that when the water molecules begin to vibrate, they quickly begin to collide with each other forming a rapidly moving compression wave. Sound travels over four times faster than in air

Explanation:

4 0

3 years ago

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What is it called when a surface takes light in without reflecting it

andrew-mc [135]

Reflection from such a rough surface is called diffuse reflection and appears matte

7 0

3 years ago

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A bicycle rider has a speed of 19.0 m/s at a height of 55.0 m above sea level when he begins coasting down hill. The mass of the

lukranit [14]

Answer:

The mechanical energy of the rider at any height will be 6.34 × 10⁴ J.

Explanation:

Hi there!

The mechanical energy of the rider is calculated as the sum of the gravitational potential energy plus the kinetic energy. Since there are no dissipative forces (like friction), the mechanical energy of the rider at a height of 55.0 m above the sea level will be the same at a height of 25.0 m (or at any height), because the loss in potential energy will be compensated by a gain in kinetic energy, according to the law of conservation of energy.

Then, calculating the potential and kinetic energy at 55.0 m and 19 m/s, we can obtain the mechanical energy that will be constant:

Mechanical energy = PE + KE

Where:

PE = potential energy.

KE = kinetic energy.

The potential energy is calculated as follows:

PE = m · g · h

Where:

m = mass of the object.

g = acceleration due to gravity.

h = height.

Then, the potential energy of the rider will be:

PE = 88.0 kg · 9.81 m/s² · 55.0 m = 4.75 × 10⁴ J

The kinetic energy is calculated as follows:

KE = 1/2 · m · v²

Where "m" is the mass of the object and "v" its velocity. Then:

KE = 1/2 · 88.0 kg · (19.0 m/s)²

KE = 1.59 × 10⁴ J

The mechanical energy of the rider will be:

Mechanical energy = PE + KE = 4.75 × 10⁴ J + 1.59 × 10⁴ J = 6.34 × 10⁴ J

This mechanical energy is constant because when the rider coast down the hill, its potential energy is being converted into kinetic energy, so that the sum of potential energy plus kinetic energy remains constant.

5 0

3 years ago

. If she

I am Lyosha [343]

Answer:

9 meters

Explanation:

Given:

Mass of Avi is, $m=40\ kg$

Spring constant is, $k=176,400\ N/m$

Compression in the spring is, $x=20\ cm=0.20\ m$

Let the maximum height reached be 'h' m.

Now, as the spring is compressed, there is elastic potential energy stored in the spring. This elastic potential energy is transferred to Avi in the form of gravitational potential energy.

So, by law of conservation of energy, decrease in elastic potential energy is equal to increase in gravitational potential energy.

Decrease in elastic potential energy is given as:

$EPE=\frac{1}{2}kx^2\\EPE=\frac{1}{2}\times 176400\times (0.20)^2\\EPE=88200\times 0.04=3528\ J$

Now, increase in gravitational potential energy is given as:

$GPE=mgh=40\times 9.8\times h=392h$

Now, increase in gravitational potential energy is equal decrease in elastic potential energy. Therefore,

$392h=3528\\\\h=\frac{3528}{392}\\\\h=9\ m$

Therefore, Avi will reach a maximum height of 9 meters.

6 0

3 years ago

Write a hypothesis about the use of an object’s physical characteristics to determine its density. Use the format "if . . . then

mash [69]

For this case you must first know the definition of density.
D = m / v
where,
m: mass
v: volume.
You can then write the following hypothesis:
IF you know two physical characteristics of an object then you can determine the density. First weigh the object, THEN measure its volume BECAUSE the density is the quotient between the mass and the volume of an object.

5 0

3 years ago

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