1. Section 1

2. Momentum  The product of the mass and velocity of an object  Momentum = mass x velocity p= mv

3. Momentum cont’d  SI units kg·m/s

4. Example A 2250 kg pickup truck has a velocity of 25 m/s to the east. What is the momentum of the truck?

5. Impulse-Momentum Theorem  Impulse- the product of the force and the time over which the force acts on an object FΔt  FΔt = ΔporFΔt = mVf – mVi

6. Example A 1400 kg car moving westward with a velocity of 15 m/s collides with a utility pole and is brought to rest in 0.30 s. Find the force exerted on the car during the collision.

7. Conservation of Momentum  The total momentum of all objects interacting with one another remains constant regardless of the nature of the forces between the objects  m 1 V 1,i + m 2 V 2,i = m 1 V 1,f + m 2 V 2,f

8. Example A 76 kg boater, initially at rest in a stationary 45 kg boat, steps out of the boat and onto the dock. If the boater moves out of the boat with a velocity of 2.5 m/s to the right, what is the final velocity of the boat?

9. Section 1

10. Centripetal Acceleration  The acceleration directed toward the center of a circular path  Centripetal means “center seeking”  Always directed toward the center of a circle

11. Centripetal Acceleration cont’d  Centripetal Acceleration=(tangential speed)² radius of circular path  a c = V t ² r

12. Example A test car moves at a constant speed around a circular track. If the car is 48.2 m from the track’s center and has a centripetal acceleration of 8.05 m/s², what is the car’s tangential speed?

13. Centripetal Force  The force directed toward the center of an object’s circular path  Example: Satellite orbiting the Earth

14. Centripetal Force cont’d  Centripetal Force = mass X (tangential speed)² radius of circular path  F c = mV t ² r

15. Example A pilot is flying a small plane at 56.6 m/s in a circular path with a radius of 188.5 m. The centripetal force needed to maintain the plane’s circular motion is 18900 N. What is the plane’s mass?

16. Section 3 & 4

17. Gravitational Force  The force of attraction between objects  Newton’s Law of Universal Gravitation - States that every object attracts every other object with a force that for any two objects is directly proportional to the mass of each object

18. Simple Machines  There are six types of simple machines

19. Lever  A lever works by moving a load around a pivot point called the fulcrum. When force is applied to the opposite end of the lever from the load, leverage created by the simple machine makes it possible to move a load that is too heavy to move without the assistance of the lever. Many of the tools used daily are levers, including scissors, pliers and hammers.

20. 3 classes of levers  First Class Example: See-saw  Second Class Example: Wheelbarrow  Third Class Example: Baseball Bat

21. Wheel and Axle  The wheel and axle make up another simple machine. A wheel and axle is a lever with a 360-degree range of motion, used to assist in the moving of objects from one point to another. The axle in this case is the fulcrum, and the wheel surface acts as the bar or board. The way the wheel and axle work is through a reduction in friction. Pulling an object creates friction, while moving an object with a wheel and axle continually transfers the load along the wheel surface, thereby reducing friction.

22. Pulley  A pulley uses a wheel and rope to change the direction of force applied to move an object. The pulley system expands on the simple machine principle of the lever. By using a rope attached at one end to a load looped over a pulley, an individual is able to use downward force to lift an object. Through the change of force from an upward motion to a downward motion, the task is easier, even though the same amount of force is applied.

23. Inclined Plane  An inclined plane is a ramp placed at an angle, used to move an object from one level to another. An inclined plane works by moving the load over a larger distance than required in lifting.

24. Wedge  The wedge is essentially two inclined planes placed against one another. A wedge works by moving against an object and creating directional pressure along the two sides of the wedge. Uses of the wedge include splitting an object or holding an object in place.

25. Screw  A screw is an inclined plane arranged around a center point.