All things with are affected by . GRAVITY All things with are affected by . Two objects, whether large or small, always have a gravitational force between them. Gravitational force as mass . Gravitational force as distance

Gravity & Projectile Motion FREE FALL: the motion of a body when _______ the force of ____________________ is acting on the body. Freefall acceleration near Earth’s surface is ____________________ If we disregard air resistance, all objects near Earth accelerate down (fall) at _____________________, abbreviated g. Because acceleration is proportional to Force/mass, sometimes we say, g= 9.81 N/kg When there is no air resistance (only gravity), a mouse and an elephant will fall _________________________=9.81m/s2

Gravity & Projectile Motion Free Fall Check Is a skydiver in free fall? Why? If a feather and a billy goat are dropped from the same height near Earth’s surface, which will reach the ground first if we disregard air resistance? Why?

Gravity & Projectile Motion Weight is different from mass. MASS: a measure of the _________________________________ _____________________________ in an object. Measured in kilograms (kg) WEIGHT: the _______________________________an object experiences because of its mass. Measured in newtons (N) or pounds (lb) Equal to mass times free-fall acceleration. weight = mass x free-fall acceleration (Fg = mg) force = mass x acceleration (F=ma) Mass = .25 kg g = 9.81m/s2 weight = mg =

Gravity & Projectile Motion What happens when things fall? An object’s falling ___________________________ is constant when air resistance ___________________________ weight. Balanced forces means constant velocity (no acceleration)… TERMINAL VELOCITY: The constant velocity of a falling object when the force of ___________________________ is equal in magnitude and opposite in direction to the ___________________________ This is the point of parachutes! Increase air resistance

Gravity & Projectile Motion Weight Check Gravity & Projectile Motion Do you have the same mass on the moon? Why? Do you have the same weight on the moon? Why?

Gravity & Projectile Motion Orbiting objects are in _______________________ The moon stays in orbit around Earth because Earth’s gravitational force ___________________________ on the moon. Two motions ___________________________ to cause orbiting. Forward motion and downward motion to Earth CENTRIPETAL FORCE: Force that causes objects to travel in a curved or circular path

What’s your weight/mass/Force 1 pound = .4535921 kilograms 1 pound = 4.4482 Newtons Take your weight in pounds = (I’ll use 100…. You can pick any number to try this with) First convert your weight to kilograms (mass) …….. x .4535921 = 100 lbs x .4535921 = 45.35921 kg Then take your mass in kg x g (9.81 m/s2) to get Fg (N) ……… x 9.81 m/s2 = 45.35921 x 9.81 = 444.97385 N Last, take your force and convert back to lbs to check… ........ / 4.4482 = 444.97385/4.4482 = 100 pounds!