In this set of worksheets students practice:
finding basic net force (addition and subtraction in one and two directions)
describing apparent motion given a different observers and the actual motion of the objects
9 student worksheets (can be used to assess student understanding)
1 set of teacher notes and suggestions
complete set of answer keys
2 (8.5 x 11) versions of the apparent motion diagrams for laminating or posting on a board for centers etc.
Meets Ohio State Standards in the 8th Grade for forces and describing motion:
Motion can be described in different ways by different observers (e.g., a pencil held in someone’s hand may appear to be at rest, but to an observer in a car speeding by, the pencil may appear to be moving backward). A force is described by its strength (magnitude) and in what direction it is acting. Many forces can act on a single object
simultaneously. The forces acting on an object can be represented by arrows drawn on an isolated picture of the object (a force diagram). The direction of each arrow shows the direction of push or pull. When many forces act on an object, their combined effect is what influences the motion of that object. The sum of all the forces acting on an object depends not only on how strong the forces are, but also in what directions they act. Forces can cancel to a net force of zero if they are equal in strength and act in opposite directions. Such forces are said to be balanced. If all forces are balanced by equal forces in the opposite direction, the object will maintain its current motion (both speed and direction). This means if the object is stationary, it will remain stationary. If the object is moving, it will continue moving in the same direction and at the same speed. Such qualitative, intuitive understandings and descriptions of inertia must be developed through inquiry activities.