Answer:
A. chemical substance whose atoms all have the same number of protons
Explanation:
An element is a substance which contains identical atoms that have the same number of protons in the nucleus.
Elements are arranged in the periodic table according to their atomic number (= number of protons): so atoms of different elements have a different number of protons in their nuclei.
For a neutral atom, the number of electrons around the nucleus is also equal to the number of protons.
Moreover, atoms of the same element can have a different number of neutrons, despite having the same number of protons - these atoms are called isotopes.
Answer: Hipparchus & Ptolemy believed sun and moon travel around circles with Earth in the middle (geocentric) while Plato and Aristotle believed Perfect unchanging heavens
Explanation: thus hipparchus and ptolemy violate early greek philosophy
The energy of a photon is given by

where

is the Planck constant
f is the frequency of the photon
In our problem, the frequency of the light is

therefore we can use the previous equation to calculate the energy of each photon of the green light emitted by the lamp:
For a merry go round with a radius of R=1.8 m and moment of inertia I=184 kg-m^2 is spinning with an initial angular speed of w=1.48 rad/s is mathematically given as
F= 618.9 N
<h3>What is the centripetal
force?</h3>
Generally, the equation for the angular speed is mathematically given as
w = v/R
Therefore
w= 4.7/1.8
w= 2.611 rad/s
Where total momentum
Tm= 642.96 + 272.32
Tm= 915.28
and total inertia
Ti= 184 + 246.24
Ti= 430.24
In conclusion, centripetal force
F= mrw^2
F = m*R*w2^2
F = 76*1.8*2.127^2
F= 618.9 N
Read more about mass
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a merry go round with a radius of R=1.8 m and moment of inertia I=184 kg-m^2 is spinning with an initial angular speed of w=1.48 rad/s in the counter clockwise direction when viewed from above a person with mass m=76 kg and velocity v=4.7 m/s runs on a path tangent to the merry go round once at the merry go round the person jumps on and holds on to the rim of the merry go round angular speed of the merry go round after the person jumps on 2.127 rad/s Once the merry go round travels at this new angular speed with what force does the person need to hold on?