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Tuesday Falcon Focus

Learn about the concepts of balanced and unbalanced forces, their effects on motion, and how to represent them using arrows. Develop models to compare and predict the resulting effects of forces on an object's motion.

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Tuesday Falcon Focus

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  1. Tuesday Falcon Focus • If an object is in motion and a force is applied to it in the __________ (same/opposite) direction of the motion, the object will slow down. • If an object is in motion and a force is applied to it in the__________ (same/opposite) direction of the motion, the object will speed up.

  2. ________ (More/Less) force is needed to change direction for an object with greater mass • ____________ is the amount of matter in an object. • ____________ is the rate of change of the position of an object.

  3. Essential Question • What is the difference between a balanced and unbalanced force?

  4. Wednesday Falcon Focus • True/False: Balanced forces acting on an object never changes the object’s motion. ____________ • True/False? On the moon, your mass would be less than it is on Earth. • True/ False? When the net force is zero, the forces on an object are balanced. _____

  5. T rue/ False? If two forces are in the same direction, they cancel each other out. ______ • T o F? Any time forces are unbalanced, an object will remain at rest ___ Essential Question: How would you construct a model (drawing) that represents an unbalance force?

  6. Thursday Falcon Focus • Complete the following: • What is the push or pull on an object that can cause it to accelerate called? __________ • What is the unit of Force? ____________

  7. When the forces acting on an object are_______________ the net force is zero. • If a person pulls on a cart to the right with a force of 10 N and a second person pulls to the left with a force of 3 N, what is the net force (and direction) on the cart? _______ • Two tugboats are moving a barge. Tugboat A exerts a force of 4000N on the barge. Tugboat B exerts a force of 6000 N in the same direction. What is the combined force on the barge? _________

  8. Essential Question • How would you construct a model (drawing) that represents a balance force?

  9. Friday Falcon Focus • Below is a diagram of a tug-o-war. Circle the correct word to complete the sentences that follow.

  10. a. The forces shown are PUSHING/ PULLING forces. • b. The forces shown are acting in the SAME DIRECTION/ OPPOSITE DIRECTION. • c. The forces are EQUAL/ NOT EQUAL. • d. The forces are BALANCED/UNBALANCED. • e. Motion is to the RIGHT/ LEFT.

  11. Essential Question • How is net force determined?

  12. BALANCE & UNBALANCE FORCES • Performance Indicator 8.P.2A.2 Develop and use models to compare and predict the resulting effect of balanced and unbalanced forces on an object’s motion in terms of magnitude and direction.

  13. QUESTION? • What is the difference between balance and unbalance forces?

  14. Force Unit • (The unit for Force is Newton (N)

  15. What are 2 things do forces have? • Forces have a magnitude (strength) and a direction.

  16. How are forces represented? • Forces can be represented as arrows with the length of the arrow representing the magnitude or strength of the force and the head of the arrow pointing in the direction of the force.

  17. What can be determined by using arrows to represent force? • Using such arrows, the resulting force (netforce) and direction can be determined.

  18. Balance vs. Unbalance Forces • Forces acting on an object can be balanced (NOT MOVING or unbalanced (MOVING).

  19. Balance Forces • *Will NOT cause a change in speed or direction of a moving object • Balanced forces acting on an object in opposite directions and equal in strength, as shown in the arrows below, do not cause a change in the speed/magnitude or direction of a moving object.

  20. Balance Forces • Objects that are not moving will not start moving if acted on by balanced forces. • For example, in arm wrestling where there is no winner, the force exerted by each person is equal, but they are pushing in opposite directions. The resulting force (net force) is zero. • 5N 5N

  21. Balance Forces • Or, in a tug of war, if there is no movement in the rope, the two teams are exerting equal, but opposite forces that are balanced. Again, the resulting force (net force) is zero. • 5N 5N

  22. Unbalanced Forces • Unbalanced forcesare not equal, and they always cause the motion of an object to change the speed and/or direction that it is moving.

  23. Unbalance Forces • When two unbalanced forces are exerted in opposite directions, their combined force is equal to the difference between the two forces. • The magnitude and direction of the net force affects the resulting motion. • This combined force is exerted in the direction of the larger force.

  24. Unbalance Forces • For example, if two students push on opposite sides of a box sitting on the floor, the student on the left pushes with less force (small arrow) on the box than the student on the right side of the box (long arrow).The resulting action(net force: smaller arrow to the right of the =) shows that the box will change its motion in the direction of the greater force as shown below: • 5N 10N 5N

  25. Practice

  26. Unbalance Forces • Or, if in a tug of war, one team pulls harderthan the other, the resulting action (net force) will be that the rope will change its motion in the direction of the force with the greater strength/magnitude as shown below: • 5N 10N 5N

  27. Practice

  28. Unbalance Forces • If unbalanced forces are exerted in the same direction, the resulting force (net force) will be the sum of the forces in the direction the forces are applied.

  29. Unbalance Forces • For example, if two people pull on an object at the same time in the same direction, the applied force on the object will be the result of their combined forces (net force or longer arrow to the right of the =) as shown below: • 5N + 10N = 15N

  30. Practice

  31. Summary • When forces act in the same direction, their forces are added. • When forces act in opposite directions, their forces are subtracted from each other. • Unbalanced forces also cause a nonmoving object to change its motion

  32. REMEMBER • If there is no net force (balance force) acting on the object, the motion does not change . • If there is net force (Unbalance force)acting on an object, the speed of the object will change in the directionof the net force.

  33. Vocabulary for the week • Magnitude: Strength of an object • Force: A push or pull • Balance force: A force that will cause no change in the motion of the object. This force does not move, and it’s net force is always zero (0)

  34. Unbalance force: A force that will cause a change in the motion of the object. This force moves, it is unequal, and it will always have a net force higher than zero. • Net force: The combination of all forces acting on an object.

  35. LETS PRACTICE!!!

  36. BALANCE & UNBALANCE FORCES STATIONS • Forces always occur in Pairs. The pairs are either balanced or unbalanced. Balanced forces do not produce any change in motion but unbalanced forces do. In the following activities identify whether or not the forces were balanced or unbalanced, whether or not the forces produced a change in motion.

  37. Balanced Forces When the net force is Zero. -> NO movement When the net force is NOT Zero. -> movement Unbalanced Forces

  38. STATION 1: Tug-A-War Analysis • View the picture and then sketch it in your PAPER:

  39. Blue Team and Red Team are playing tug-of-war. If Blue Team pulls the rope to the right with a force of 800N and Red Team pulls the rope to the left with a force of 800N, what will happen to the flag in the middle of the rope? • Explain. • Is this force balanced or unbalanced? • Create a representation of the picture below with arrows. (Include numbers as well.

  40. Station 2: Dominoes • Set up the dominoes in a row so that they will touch each other when they fall. • What type of force will make the dominoes fall? _________________ • Touch 1 domino so that the others are knocked over. • Draw your domino set up below and draw arrows to show the direction of movement.

  41. Station 3: Paddle Ball • With a lab partner: play PADDLE BALL 2 or 3 times. • WHO WON? __________________ • What is the force that makes the ball stop? ___________________ • Is there a different force making the ball fall towards the ground? ___________ If so, what is it called? ___________________ • When the paddle stops the ball, is that force moving in the same direction as the ball? ___________

  42. STATION 4: THE BALL • Place the ball on the counter, where the “X” is. • 2. Write ON YOUR PAPER: Is this an example of balanced or unbalanced force? Why? • 3. GENTLY bounce the ball so that it bounces up from the floor to your hand. • 4. Draw the movement ON YOUR PAPER and label the direction of forces. • 5. Write ON YOUR PAPER: Is this movement an example of balanced or unbalanced force? Why?

  43. Station 5: Pulling The Book • Place the book with the string around it on one end of a table. • Hook a spring scale to the string around the book and slide it across the table at a constant speed. • How much force was needed to pull the book? _________________N

  44. REPEAT STEP 1. Put several straws under the book spaced (SPACED OUT EVENLY). • Attach the spring scale to the string around the book and pull it at a constant speed across the table. • How did the force needed to pull the book on straws compare with the force needed to drag the book without the straws?

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