Answer: To find the atomic mass of an atom of an element, add up the mass of protons and neutrons.
Explanation: Find the atomic mass of an isotope of carbon that has 7 neutrons. You can see from the periodic table that carbon has an atomic number of 6, which is its number of protons.
1).B
2.)C
i think the reason was because of the pangea theory that continents where once one big continent and over time it began to split
B) Light slows down when it passes into a denser medium.
Answer:
0.001 s
Explanation:
The force applied on an object is equal to the rate of change of momentum of the object:

where
F is the force applied
is the change in momentum
is the time interval
The change in momentum can be written as

where
m is the mass
v is the final velocity
u is the initial velocity
So the original equation can be written as

In this problem:
m = 5 kg is the mass of the fist
u = 9 m/s is the initial velocity
v = 0 is the final velocity
F = -45,000 N is the force applied (negative because its direction is opposite to the motion)
Therefore, we can re-arrange the equation to solve for the time:

Wave speed = (wavelength) x (frequency)
Wave speed = (3 m) x (15 Hz)
<em>Wave speed = 45 m/s</em>