## Activity Overview

Creating force diagrams is an important skill for students to acquire so that they are able to understand and describe the forces acting on an object. In this activity, students will create quick, clear, and easy force diagrams. The instructions in this activity are specific to the example storyboard above. You can alter this storyboard and add it as a template, or create your own scenarios for students to diagram by editing the instructions.

Forces are a vector quantity, meaning they have both size and direction. We can represent these forces using an arrow. The direction of the arrow represents the direction of the force and the length of the arrow represents the size of the force. If the forces are balanced, they are said to be equal and opposite. Balanced forces have a resultant (net) force of zero. When there is no resultant force, the object will either travel at a constant speed if it was already moving, or remain stationary if it wasn’t moving. If the forces are unbalanced, then there is a resultant force. If the object was stationary, the resultant force will cause the object to move.

#### Light Modifications

You can stretch more advanced students by getting them to draw the resultant forces in each of the examples. You can simplify these diagrams even more by using shapes instead of images of the objects.

In terms of differentiation you can make this task more easily accessible by giving students a list of the forces they need to include in each cell. To stretch your gifted and talented learners, give them more complex situations to draw diagrams for, where the forces don’t lie on the x, y, z axis. An example of this is given in the storyboard with the rappeler.

## Template and Class Instructions

(These instructions are completely customizable. After clicking "Copy Activity", update the instructions on the Edit Tab of the assignment.)

Student Instructions

Create force diagrams in a range of different contexts. Remember forces have both a size and direction. This means you need to be careful about the direction of the arrow and its length.

1. Click "Start Assignment".
2. The situations on the left are a rocket accelerating upwards, a boat floating in the water, and at the bottom of the bungee cord when the person is stationary.
3. Use arrows from the shapes menu to add force diagrams to the cells on the right. Change the arrow to make them the correct length and make sure they are pointing in the correct direction.
4. Label your arrows using Textables.
5. Underneath your force diagram, write a description of the forces. Say whether they are balanced or unbalanced, and what effect this has on the object's motion.

#### Lesson Plan Reference

Common Core Standards
• [SCI-3-PS2-2] Make observations and/or measurements of an object’s motion to provide evidence that a pattern can be used to predict future motion.

## Rubric

(You can also create your own on Quick Rubric.)

Force Diagrams
Draw a force diagram for the given situation.
Proficient
33 Points
Emerging
16 Points
Beginning
0 Points
Force Arrows and Labels
• All the force arrows are in the correct direction and have the correct length.
• All the forces are labeled.
• All the force arrows are in the correct direction.
• Most of the forces are labeled.
• Some the force arrows are in the correct direction.
• Some of the forces are labeled.
• Description
• The description of the forces is clear and concise.
• The forces have been described as balanced/unbalanced pairs.
• The motion of the object is described using the resultant force.
• The description of the forces can be understood, but is confusing.
• The forces have been described as balanced/unbalanced pairs.
• The description of the forces cannot be understood.
• Evidence of Effort
Work is well written and carefully thought out.
Work shows some evidence of effort.
Work shows little evidence of any effort.