Net Forces

Master net forces! Calculate and analyze balanced/unbalanced forces to predict motion. Physics practice for students.

1. Please watch this video for some info about forces. 2. When two or more forces are acting on the same object, in the SAME direction, you ADD the forces. Net force is a vector, so you must include the direction. The unit of force is a Newton (N).25 N + 20 N = 5 N 45 N 10 N 3. When two forces are acting on the same object in OPPOSITE directions, you subtract the forces. Net force is a vector, so you must include the direction.12 N - 10 N = 22 N 12 N 2 N 4. When forces are BALANCED, the net force is zero (0) To the right To the left 5. A big tractor pulls a box with a force of 400N to the left. A small tractor pulls that same box with a force of 200N to the right. What is the net force on the box and what direction will it move? net force is 600 Nthe box will not move net force is 200 Nthe box will move to the right net force is 200 Nthe box will move to the left. net force is 600 Nthe box will move to the left 6. In the diagram 2 people are pushing books. What is the net force being applied to the books? 25 N 5 N to the right 5 N to the left zero, the forces are balanced 7. In the diagram two people are pushing books. What is the net force being applied to the books? 21 N 19 N to the right 19 N to the left zero, the forces are balanced 8. The net force is 7 NAre the forces balanced or unbalanced? unbalancedWhich direction would the cart move? to the right 9. The boy in the picture is trying to pull a dog on its leash, but the boy and the dog are moving in the same direction. Which of the following best describes this situation? The forces are balanced, and the net force is zero. The forces are unbalanced, and the boys force is greater. The forces are unbalanced, and the dog's force is greater. The forces are balanced, and the dog is stronger than the boy. 10. What is the net force? 15 N 5 N to the left 5 N to the right 15 N left 11. What is the net force? 19 N to the right 4 N to the left 7 N to the right 3 N to the right 12. What is the net force? 25 N 10 N down 5 N up 10 N up 13. These boys are both pulling with 10 N of force. What will happen? The boy in blue will win. They will not move at all. The boy in red will win. Both will fall down. Draw a diagram for each scenario and solve 14. A boy pulls a wagon with a force of 6N to the right as another boy pushes with a force of 4 N to the left. What is the net force? 15. Mr. Smith and his wife were trying to move their new chair. Mr. Smith pulls with a force of 30 N while Mrs. Smith pushes with a force of 25 N in the same direction. What is the net force? 16. The classes are playing tug of war. Mrs. Larson's homeroom pulls with a force of 45 N. Ms. Mitko's homeroom pulls with a force of 50 N in the opposite direction. What is the net force and who won? 17. Draw a picture below that shows an example of a balanced force (examples: a bird's nest in a tree, a hat on a person's head, or a light hanging from a ceiling). Show the forces acting on the object. In a separate picture show what would happen to the object if the forces became unbalanced. 18. What is a balanced force? (What doe it mean to have balanced forces?) 19. What is an unbalanced force? (What does it mean to have unbalanced forces?)