Answer:
8.56 m/s2
Explanation:
Using law of energy conservation while taking into account of the rotational and translation kinetic energy, when the solid cylinder rolls down the incline we have the potential energy converted to kinetic energy:


where m is the mass,
is the moments of inertia of the solid cylinder
is the angular speed of the cylinder



So if you plot a liner chart of h vs
and get a slope of 6.42 then that means 3/(4g) = 6.42 so 
The gravitational acceleration on this planet is 8.56 m/s2
Answer:
The objects were 1.8m apart.
Explanation:
We will start stating the Coulomb's Law. It says that:

Where F_e is the electric force between the objects, q_1 and q_2 are the magnitude of the charge of the objects, r is the distance between them and K is the Coulomb's constant (
in vacuum). Solving for the distance r we have:

Plugging the given values into this equation, we obtain:

In words, the two charged objects were 1.8m apart.
The atomic number of Aluminum is 13. The atomic number represents the number of protons in an atom.
Answer:
G M m / R^2 = F force of attraction for proton
K e^2 / r^2 = F force of attraction between 2 protons
G M m / R^2 = K e^2 / r^2
r^2 = K e^2 R^2 / (G M m)
r^2 = 9E9 * (1.6E-19)^2 * (6.37E6)^2 / (6.67E-11 * 5.98E24 * 1.7E-27)
r^2 = 9 * 2.56 * 40.6 / (6.67 * 5.98 * 1.7) * 10^-19
r^2 = 1.38 * 10^-30
r = 1.17E-15 m