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4 years ago

What is matter? Give a grade 10/11/12 understanding.

1 answer:

3 0

Matter can be many things, but is mostly made of atoms. Atoms are small things that cannot be seen directly, as lights either passes through it or alters it. However, we know that atoms are made of 3 parts, those being the proton, neutron, and electron.

Protons have a positive electromagnetic charge.

Neutrons have no charge.

Electrons have a negative charge equal to the protons positive charge.

Protons and neutrons make up what's called the nucleus, which is orbited by the electrons.

Protons and neutrons also share another thing in common, that being their composition.

Until relatively recently, we thought that these were the smallest particles in the universe, and indestructible. However, modern discoveries have revealed that they are actually made of quarks and gluons.

These are actually indestructible, being part of the group that is elementary particles.

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It is well known that runners run more slowly around a curved track than a straight one. One hypothesis to explain this is that

barxatty [35]

Answer:

$percentage = 6.27 %$

Explanation:

As we know that when runner is moving on straight track then the net force on his feet is given as

$F_s = mg$

while when runner is moving on circular track then we have

$F_c = \sqrt{(mg)^2 + (\frac{mv^2}{R})^2}$

$F_c = m\sqrt{g^2 + \frac{v^4}{R^2}}$

$F_c = m\sqrt{9.8^2 + \frac{8^4}{18^2}}$

$F_c = m(10.42)$

now percentage change is given as

$percentage = \frac{F_c - F_s}{F_s} \times 100$

$percentage = \frac{m(10.42) - m(9.81)}{m(9.81)}\times 100$

$percentage = 6.27 %$

6 0

3 years ago

The energy from radiation can be used to cause the rupture of chemical bonds. A minimum energy of 242kJ/mol is required to break

iris [78.8K]

Answer:

The longest wavelength of radiation that passesses the necessary energy for breaking the Cl- Cl bond (in Cl2) is approximately 494.2 nm, which corresponds to the visible spectrum.

Explanation:

In order to answer this question we need to recall that the energy of a photon is given by:

E = hc/lambda, where

E = energy

h = Planck's constant

c = speed of light in vacuum

lambda = associated photon wavelength

In order to perform the calculations, first we need to change the units of 242kJ/mol to J. For doing this, we to divide by Avogadro's number and multiply by a 1000:

242kJ/mol = (242kJ/mol)*(1mol/6.022x10^23 particles)*(1000J/1kJ)= 4.0186x10^-19 J

Now, we simply solve for lambda and substitute the appropriate values in the energy equation:

lambda = hc/E = (6.626x10^-34 J s)*(3x10^8 m/s)/(4.0186x10^-19 J) = (1.986x10^-25 J m)/(4.0186x10^-19 J) = 4.942x10^-7 m = 494.2x10^-9 m = 494.2 nm

Therefore, the wavelength for a photon to break the Cl-Cl bond in a Cl2 molecule should be 494.2 nm at most, which corresponds to the visible spectrum (The visible spectrum includes wavelengths between 400 nm and 750 nm).

3 0

4 years ago

astronaut is traveling in a space vehicle moving at 0.510c relative to the Earth. The astronaut measures her pulse rate at 61.0

lisabon 2012 [21]

Answer:

45.13 beats/min

Explanation:

Speed of space vehicle = 0.51c

the pulse rate measured by the astronaut= 61.0 beats per minute

Pulse rate measured by the Earth observer is given by

$=(pulse\ rate)\sqrt{1-\frac{v^2}{c^2} }$