science help!!!?

Question

1. The gravitatinal force that exerts on the moon equals 2.03*10 to 20th power N. The moon's mass 7.35*10 to the 22 power kg. What is the acceleration of the moon due to Earth's gravitational pull?

Answer 1

Use Newton's law:

F = m*a

F = gravitational force = 20.3*10^23 N

Since newtons are a unit of force, the units are mass*acceleration, again from Newton's law. mass is kg, and the SI units for acceleration are m*s^-2, or "meters per second squared).

mass = 7.35*10^22 kg.

So the kg units cancel out and now you just need the acceleration:

20.3*10^23 (kg-m-s^-2) = 7.35*10^22 kg * a (m-sec^-2)

So just solve for a. Since you're doing a units analysis (always, always, always write out the units when you're doing these kinds of problems), you know that all you have to do is solve for "a" and you'll have the acceleration.

Finally, make sure you don't have to multiply by any gravitational constants (you don't since you're working in SI). However, if you work in units, you wil always know if you're getting the right answer. Writing out the kg, N, meters, seconds, and every other unit will sometimes save you even if you have no idea how to solve the problem, because you know the units must always match. Good Luck.

Answer 2

acceleration = force / mass
That's Newton's Second Law.