Warm-up: Anticipation Guide

1. Warm-up: Anticipation Guide Directions: Carefully read the statements on your anticipation guide. Think about the statement and determine if you generally agree or disagree with it by marking an X next to your answer. Be sure to provide an explanation for your response by writing it next to the “Why?” Next: Look at the basket of materials in front of you. Using only those materials, your desk, your book, and/or your body, find a way to justify your answer.

2. Anticipation Guide • An object can move with or without a force being applied. • Agree ____ Disagree _X_ • Why? Newton’s first law explains that an object in motion will stay in motion while an object at rest will stay at rest unless acted upon by an unbalanced force. • Example: Planets rotating in space, spinning top, eggs • When forces act in opposite directions, they always cancel each other out. • Agree ____ Disagree _X_ • Why? Only if they are balanced will they cancel each other out. If they are unbalanced, they will not. • Example: Arm wrestling, tug-of-war

3. Anticipation Guide • When an equal force acts on two different objects, the objects will move at the same speed in the same direction. • Agree ____ Disagree _X_ • Why? It would depend on the mass of the objects. F=MA (Newton’s 2nd law) • Example: Spring scales pulling objects with different masses • When forces act in the same direction, the net force can be found by adding the strengths of the individual forces. • Agree _X_ Disagree ____ • Why? The forces will combine together • Example: Tug of war, getting a friend to help you lift something heavy 

4. Anticipation Guide • Gravity pulls equally on all objects everywhere on earth. • Agree _X_ Disagree ____ • Why? Gravitational pull is the same regardless of where you are. • Example: No matter where I drop a ball around a room, it still falls back to the Earth. • The mass of an object will affect how fast it moves or falls to the earth. • Agree ____ Disagree _X_ • Why? Rate of acceleration (9.8m/s2) doesn’t change regardless of mass •  Example: dropping similar objects with different masses

5. Anticipation Guide • Smooth surfaces produce less friction than rough surfaces. • Agree _X_ Disagree ____ • Why? Less surface area to come in contact with other material • Example: sand paper vs. waxed paper • You and a friend are at the park playing on a seesaw. In order for it to move, the forces must be unbalanced. • Agree _X_ Disagree ____ • Why? Newton’s first law explains that an object in motion will stay in motion while an object at rest will stay at rest unless acted upon by an unbalanced force. •  Example: Washers on ruler seesaw

6. Anticipation Guide • A boat is cruising down the river. Seated passengers on the boat are moving in comparison to the boat. • Agree ____ Disagree _X_ • Why? The distance between the passengers and the boat doesn’t change. Therefore, they are not moving in comparison to the boat. • Example: People in cars don’t move in relation to the car. • A car is traveling down the highway and stops suddenly for a red light, the force applied to the brakes will cause everything in the car to stop moving. • Agree ____ Disagree _X_ • Why? Newton’s first law explains that an object in motion will stay in motion while an object at rest will stay at rest unless acted upon by an unbalanced force. • Example: Washers on car will fly when car stops.

7. MOTION Standards: S8P3 – Investigate the relationship between force, mass, and the motion of objects. S8P3a – Demonstrate the effect of balanced and unbalanced forces on objects in terms of gravity, inertia, and friction. Essential Questions: How can you describe an object’s motion? What causes an object’s motion to change?

8. Motion • An object is in motion if its distance from another object is changing.

9. Reference Point • A place or object used for comparison to determine if something is in motion.

10. Measuring Distance • Scientists use the INTERNATIONAL SYSTEM OF UNITS (SI UNITS) to communicate their measurements clearly.

11. Speed • The speed of an object is the distance the object travels per unit of time. • Speed = Distance Time

12. Average Speed • The total distance traveled divided by the total time. • Average Speed = Total Distance Total Time

13. Instantaneous Speed • The rate at which an object is moving at a given instant in time.

14. Velocity • Speed in a given direction.

15. Slope • The steepness of a line on a graph. • Slope = Rise Run

16. Assignment: • Make sure you have completed workbook pages 128-129 #’s 1-9 • Complete workbook page 130-132 #’s 1-8

17. Warm-up: • Your mom asks what you what you’ve been learning about in science. You mention things like, “motion, reference point, speed, average speed, instantaneous speed, and velocity,” but she doesn’t know what these words mean. Without giving her a word-for-word definition of each term, how would you explain it to her? Write a one-paragraph response.

18. Acceleration • The rate at which velocity changes. • Refers to increasing speed, decreasing speed, or changing direction. • Acceleration = final speed – initial speed time

19. Practice: • In your composition book, solve the following: If a snowflake is falling at 1m/s, and 4 seconds later, it is falling at 5m/s, what is its rate of acceleration?

20. Force • A force is a push or a pull, described by its strength and the direction in which it acts, measured in SI unit called the NEWTON.

21. Net Force • The combination of all forces acting on an object; it determines whether an object moves and also in which direction it moves.

22. Unbalanced Forces • Cause an object to start moving, stop moving, or change direction. • Result in a net force and cause a change in the object’s motion.

23. Balanced Forces • Equal forces acting on one object in opposite directions. • Do not change the object’s motion.

24. Assignment: • complete workbook pages 137-138 #’s 1-12

25. Friction • The force that two surfaces exert on each other. • Strength depends on how hard the surfaces push together and the types of surfaces involved.

26. Static Friction • The friction that acts on objects that are not moving. • Ex: your desk sitting on the floor.

27. Sliding Friction • The friction that occurs when two solid surfaces slide over each other. • Ex: sticky ballet shoe powder to prevent slipping

28. Rolling Friction • The friction that occurs when an object rolls across a surface. • Ex: wheels on skateboards

29. Fluid Friction • The friction that occurs when a solid object moves through a fluid. • Ex: cyclists’ streamlined helmets

30. Inquiry: • If I were to drop a golf ball and a ping-pong (table tennis) ball from the same height at the same time, which would reach the ground first? Explain your answer.

31. Gravity • A force that pulls objects toward each other. • The LAW OF UNIVERSAL GRAVITATION states that the force of gravity acts between all objects in the universe.

33. Factors Affecting Gravity • MASS – a measure of the amount of matter in an object (kg). • DISTANCE BETWEEN OBJECTS – the farther apart two objects are, the lesser the gravitational force between them.

34. Weight and Mass • MASS – a measure of the amount of matter in an object (kg). • WEIGHT– The force of gravity on a person or object at the surface of a planet..

35. Free Fall • When the only force acting on an object is gravity, it is in free fall. • The force of gravity is unbalanced, which causes an object to accelerate. • Acceleration is 9.8m/s2

36. Air Resistance • A type of fluid friction objects falling through air experience.

37. Terminal Velocity • The greatest velocity a falling object reaches when the force of air resistance equals the weight of the object.

38. Projectile Motion • An object that is thrown is a projectile. • A projectile will fall at the same rate as any dropped object.

39. Warm-up: • Recall Newton’s 1st and 2nd Laws… try to put them in your own words!

40. Newton’s First Law (Inertia) An object at rest will remain at rest, and an object moving at a constant velocity will continue moving at a constant velocity, unless it is acted upon by an unbalanced force.

41. Inertia depends on mass. The more mass an object has, the harder it is to change the rate of acceleration.

42. Newton’s Second Law Acceleration depends on the object’s mass and on the net force acting on the object. Acceleration = net force mass

43. Newton’s Third Law If one object exerts a force on a second object, the second object exerts a force of equal strength in the opposite direction on the first object.

44. Momentum A characteristic of a moving object that is related to the mass and velocity of the object. Momentum = Mass x Velocity

45. Law of Conservation of Momentum The total momentum of any group of objects remains the same, or is conserved, unless outside forces act on the objects.

46. Centripetal force • Any force that causes an object to move in a circular path. Amusement Park Fun

47. Displacement • How far an object changes its position from start to finish.

48. Pressure • A force exerted over an area on the surface of an object.

49. Pressure decreases as the area over which a force is distributed increases. • It is measured in Newtons/square meter (N/m2) …aka the PASCAL • Write this ------------

50. Fluid Pressure • All of the forces exerted by the individual particles in a fluid combine to make up the pressure exerted by the fluid. • Air pressure is an example of fluid pressure.