Presentation on theme: "Free Fall The acceleration of gravity (g) for objects in free fall at the earth's surface is 9.8 m/s2. Galileo found that all things fall at the same rate."— Presentation transcript:
1 Free FallThe acceleration of gravity (g) for objects in free fall at the earth's surface is 9.8 m/s2.Galileo found that all things fall at the same rate.
2 Free Fall The rate of falling increases by 9.8 m/s every second. Height = ½ gt2For example:½ (9.8 )12 = 4.9 m ½(9.8)22 = 19.6 m½ (9.8)32 = 44.1 m½ (9.8)42 = 78.4 m
3 Free FallA ball thrown horizontally will fall at the same rate as a ball dropped directly.
4 Free FallA ball thrown into the air will slow down, stop, and then begin to fall with the acceleration due to gravity. When it passes the thrower, it will be traveling at the same rate at which it was thrown.
5 Free FallAn object thrown upward at an angle to the ground follows a curved path called a parabola.
6 Air Resistance In air… In a vacuum A stone falls faster than a feather Air resistance affects stone lessIn a vacuumA stone and a feather will fall at the same speed.
7 Air Resistance Free Fall A person in free fall reaches a terminal velocity of around 54 m/sWith a parachute, terminal velocity is only 6.3 m/sAllows a safe landing
8 Air Resistance Ideal angle for a projectile In a vacuum, maximum distance is at an angle of 45oWith air resistance (real world), angle is lessBaseball will go furthest hit at an angle of around 40o
9 First Law of MotionThe first law of motion states: If no net force acts on it, an object at rest remains at rest and an object in motion remains in motion at a constant velocity.
10 Inertia and MassInertia is the apparent resistance an object offers to any change in its state of rest or motion.
11 Second Law of Motion F = Ma Newton's second law of motion states: The net force on an object equals the product of the mass and the acceleration of the object. The direction of the force is the same as that of the acceleration.F = Ma
12 Second Law of MotionA force is any influence that can cause an object to be accelerated.
13 Mass and WeightWeightDefinition: The force with which an object is attracted by the earth’s gravitational pullExample: A person weighing 160 lbs is being pulled towards the earth with a force of 160 lbs (712 N).Near the earth’s surface, weight and mass are essentially the same
14 Third Law of MotionThe third law of motion states: When one object exerts a force on a second object, the second object exerts an equal force in the opposite direction on the first object.
16 Circular MotionCentripetal force is the inward force exerted on an object to keep it moving in a curved path.Centrifugal force is the outward force exerted on the object that makes it want to fly off into space.