3.  Gravity is 9.8 or ~10 m/s 2  If dropped from rest: y = -½ gt 2

4. X-motion is INDEPENDENT of Y-motion An object is thrown horizontally with an initial speed of 10 m/s. It hits the ground 4 seconds later. How far did it drop in 4 seconds? -80m From a height of 100 m, a ball is thrown horizontally with an initial speed of 15 m/s. How far does it travel horizontally in the first 2 seconds? 30m A rolling ball falls off a lab desk with a velocity of 2 m/s. The height of the lab desk is 1 m. How far away does the ball land?

6. Any push or pull is called a force (N) - Tension - Gravitational force - Air resistance - Normal force - Frictional force - Electrostatic force - Nuclear forces

7.  Law of Inertia – A body at rest wants to stay at rest or a body in motion wants to stay in motion unless acted upon by an outside force

8.  ΣF = ma  Force is measure in Newtons (kg●m/s 2 )  Can be used in component directions as well. So…. ΣF x = ma x ΣF y = ma y

9.  For every action, there is an equal but opposite reaction

10. What net force is required to maintain a 5000 kg object moving at a constant velocity of magnitude 7500 m/s? How much force is required to cause an object of mass 2 kg to have an acceleration of 4 m/s 2 ? An object feels two forces; one of strength 8 N pulling to the left and one of strength 20 N pulling to the right. If the object’s mass is 4 kg, what is its acceleration? A book whose mass is 2 kg rests on a table. Find the magnitude of the force exerted by the table on the book. 8N 3 m/s 2 20 N

12.  A can of paint with a mass of 6 kg hangs from a rope. If the can is to be pulled up to a rooftop with a constant velocity of 1 m/s, what must the tension in the rope be? 60 N  What force must be exerted to lift a 50 N object with an acceleration of 10 m/s 2 ? 100 N

13.  The force that is perpendicular to the surface  A book whose mass is 2 kg rests on a table. Find the magnitude of the normal force exerted by the table on the book. 20 N

14. Parallel to the surface and opposite the direction of the intended motion 1) Static friction – the force that resists movement F s ≤ μ s F N 2) Kinetic friction – the force that acts on a moving object F k = μ k F N

15.  A crate of mass 20 kg is sliding across a wooden floor. The coefficient of kinetic friction between the crate and the floor is 0.3 ◦ Determine the strength of the friction force acting on the crate. 60 N ◦ If the crate is being pulled by a force of 90 N (parallel to the floor), find the acceleration of the crate. 1.5 m/s 2

18. A block slides down a frictionless, inclined plane that makes a 30 degree angle with the horizontal. Find the acceleration of this block. 5 m/s 2 Suppose the same block slides down the same inclined plane with a coefficient of kinetic friction of 0.3. Find the acceleration of the block

20. A c = v 2 /r F c = mv 2 /r Anything moving in circular motion at constant speed (changing velocity) must experience a net force. This net force is called a centripetal force. An object of mass 5 kg moves at a constant speed of 6 m/s in a circular path of radius 2 m. Find the object’s acceleration and the net force responsible for its motion. 18 m/s 2 ; 90 N An athlete who weighs 800 N is running around a curve at a speed of 5.0 m/s with a radius of 5.0 m. Find the centripetal force acting on him & what provides the centripetal force? 400 N & static friction

21. A roller-coaster car enters the circular loop portion of the ride. At the very top of the circle, the speed of the car is 15 m/s, and the acceleration points straight down. If the diameter of the loop is 40 m and the total mass of the car is 1200 kg, find the magnitude of the normal force exerted by the track on the car at this point. 1500 N How would the normal force change if the car was at the bottom of the circle? 25,500 N

22. F = Gm 1 m 2 / r 2 G = 6.67 x 10 -11 N ● m 2 / kg 2 “Any two objects of mass experience a force of attraction that is directly proportional to the masses involved and inversely proportional to the distance between the objects squared.” r- is the distance from the centers of each object.

23. F = Gm 1 m 2 / r 2 G = 6.67 x 10 -11 N ● m 2 / kg 2  Given that the radius of the earth is 6.37 x 10 6 m, determine the mass of the earth. 6.1 x 10 24 kg  An artificial satellite of mass m travels at a constant speed in a circular orbit of radius R around the earth (mass M). What is the speed of the satellite? √GM/R