Transcript Friction and Gravity

Gravity
Friction
 The force that 2 surfaces exert on each other when they rub against
each other is called FRICTION
GRAVITY
 The force that pulls objects towards each other is called
GRAVITY
 Universal Gravitation
 Universal Gravitation means that
 ALL OBJECTS ARE ATTRACTED TO EACH OTHER
Factors Affecting Gravity
 2 factors that affect gravity are MASS AND DISTANCE
 MASS is a measure of the amount of matter in an object.
 The SI unit of mass is the KILOGRAM
 MORE mass and SHORTER distance means greater gravitational
force.
 Weight and Mass
 MASS is the amount of matter in an object; WEIGHT is the force of
gravity on an object.
Gravity and Motion
 Free Fall
 When the only force acting on a object is GRAVITY the object is said
to be in FREE FALL
 Gravity is an UNBALANCED FORCE
 Free Fall accelerates at a rate of 9.8 M/S2
 ALL objects fall at the same rate.
Air Resistance
 A type of fluid friction is AIR RESISTANCE
 Air Resistance is an UPWARD FORCE
 TERMINAL VELOCITY is reached when the force of air
resistance equals the weight of the object.
Projectile Motion
 A THROWN object is called a projectile
 A projectile will fall at the SAME rate as a dropped object.