Answer:
1. Two people stand on the same side of a large tire. Both people pull the tire with equal force.
2. an object’s ability to not change its motion
3. The car moves forward, while inertia keeps the balloon in place.
4. The unbalanced forces of air resistance and gravity slow the airplane and pull it down.
5. The force acting on the object must be unbalanced.
Answer:
30, 50
Explanation:
Hello,
In this since an element's atomic number is equal to the number of protons in its atom, we can infer that selenium's atomic number is 30. Moreover, due to the fact the the neutrons are equal to the atomic mass minus the atomic number or the number of protons, by knowing the number of neutrons we compute the atomic as follows:

Thus, answer is 30, 50.
Best regards.
Answer:
the density of lithium will be equal to: 0.582 g/cm^3
Explanation:
We have the following data:
a = 430 pm = 4.3x10^-8 cm
molar mass of lithium MM = 6.97 g/mol
Since the cubic cell of lithium is cubic centered in the face, its value of Z will be equal to 4
Avogadro´s number AN = 6.022x10^23 particles/mol
using the following formula we will calculate the density of lithium:
d = (Z*MM)/(a^3*AN) = (4*6.97)/((4.3x10^-8)^3*(6.022x10^23)) = 0.582 g/cm^3