1. Notes: Forces Big “G” and little “g” Newton’s Law of Universal Gravity F g, the force of attraction between two objects is directly proportional to the products of the masses of the objects, and inversely proportional to square of the distances between their centers of mass F g = G m 1 m 2 r 2 G = 6.67 x 10 -11 Nm 2 kg 2 r m1m1 m2m2 F1F1 F2F2

2. F g = G m 1 m 2 r 2 Force of gravity (Fg) between large masses (objects) is greater than between small masses (objects). Force of gravity (Fg) decreases as distance between objects increases. r m1m1 m2m2 F1F1 F2F2

3. Acceleration due to the force of gravity All falling objects on earth, in the absence of air resistance, accelerate at the rate of 9.8 m/s 2 g = 2  d = 9.8 m/s 2 t 2 V f = g  t V f = √ 2g  d  d = 1gt 2 2 air resistance (or drag) the force exerted by air on a moving object terminal velocity the largest velocity that is reached by a falling object when air resistance balances the pull of gravity, an object stops accelerating and its speed remains constant

4. Big “G”, Little “g”, and “F g” “G” is a constant value used to calculate the force of gravity between two objects. G = 6.67 x 10 -11 Nm 2 kg 2 “g” is the acceleration due to the force of gravity pulling on an object “F g ” is the actual pull, or force, of gravity on an object. It is also the weight of an object. “Pulling ‘g’s’ ” in an aircraft, or amusement park ride, is actually the measure of how many times your weight “F g “ your body is experiencing.