Complete a free body diagram question

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Draw forces

Select drawn forces

Edit drawn forces

Delete a drawn force

A free body diagram question requires you to draw forces at specific angles from one or more starting points (called control points) on top of a background image.

A free body diagram response area showing a box on an incline with one control point.

Draw forces

TIP: Here's some helpful information about drawing forces for your response to free body diagram questions:

  • The forces that you draw on the free body diagram always originate from control point(s) that are pre-defined by your instructor.

Control point identified as "A" on a free body diagram.

  • Your free body diagram question may have more than one control point that you can draw forces from.

Multiple control points on a free body diagram; one object in the diagram has control point "A" and the second object in the diagram has control point "B".

  • Multiple forces can be drawn from a single control point.

Natural force, gravity, and static friction are all originating from a single control point "A" for a box on an incline.

  • Arrow length of your drawn force is disregarded for grading since force magnitudes aren't considered for Möbius free body diagram questions.

You can draw the forces for a response to a free body diagram question in two ways:

  • Freehand
  • Force type menu

Freehand

You can draw forces using the freehand method for a free body diagram question:

  1. Click on the control point of interest and drag your cursor to the angle of the force you want to draw. Release your cursor when the arrow is at the intended angle.

A natural force force arrow is drawn from a control point "A" for a box on an incline.

NOTE: The drawn angle is then indicated in the angle field in degrees when you release your cursor.

The numerical value of the drawn angle appears in the angle field to the right of the Choose a Type drop-down menu.

  1. Click Choose a Type from the force type menu and select the force that's represented by the arrow you just drew in step 1.

A range of available forces are displayed in the "Choose a Type" drop-down menu.

NOTE: There may be extra forces available in the force type menu for you to choose from to assess your understanding!

  1. Click on the background of the free body diagram response area to confirm your drawn force.

The cursor is pointed at the background of the free body diagram image.

NOTE: The newly-drawn force's handle disappears and the arrow turns from blue to black when it's confirmed.

  1. Repeat steps 1 to 3 for as many forces and control points as needed to answer the question.

Force type menu

You can draw forces using the force type menu for a free body diagram question:

  1. Click Choose a Type from the force type menu to select the type of force you want to draw.

A range of available forces are displayed in the "Choose a Type" drop-down menu.

NOTE: There may be extra forces available in the force type menu for you to choose from to assess your understanding!

TIP: Does your free body diagram question have more than one control point? You'll need to define the control point that you want the force to originate from by selecting the desired control point from the Origin drop-down list, and then continue to step 2.

The Origin drop-down menu appears when the question involves more than one control point. The menu appears between theforce type menu and angle field.

  1. Enter a value in degrees (°) in the angle field that you want to use to draw the selected force.

The angle field is to the right of the force type menu.

NOTE: Valid angles are between -180° and 360°, inclusive. Half angles are also accepted (Example — 100.5°).

  1. Click Draw.

The "Draw" button is to the right of the angle field.

  1. Click on the background of the free body diagram response area to confirm your drawn force.

The cursor is pointed at the background of the free body diagram image.

NOTE: The newly-drawn force's handle disappears and the arrow turns from blue to black when it's confirmed.

  1. Complete steps 1 to 4 for as many forces and control points as needed to answer the question.

TIP: Alternatively, to draw additional forces using the force type menu:

  1. Click the hamburger menu of the response area.

The free body diagram menu is the first menu within the response area.

  1. Click New Force.

The "New Force" menu option is the first option in the free body diagram hamburger menu.

  1. Repeat steps 1 to 3 of the Force type menu subsection for as many forces and control points as needed to answer the question.

Select drawn forces

Clicking on a force arrow selects it.

A selected force turns from black to blue and its handle appears (Example — the Normal Force (N) arrow is selected):

A box on an incline has gravity, static friction, and the normal force drawn. The normal force is selected and is blue with a visible force handle.

TIP: An alternative to select a force is to click the hamburger menu to view and select a drawn force from the Drawn list.

Forces that have been drawn are listed and can be selected from the free body diagram menu after the "New Force" option.

Edit drawn forces

You can edit these components of your drawn force(s):

  • Label (Example — you meant to label a force as Normal Force (N) instead of Force of Gravity (Fg))
  • Angle (Example — you meant to position the force arrow at 125° instead of 94°)

Label

To edit a drawn force's label:

  1. Select the force arrow that you want to edit.

A box on an incline has the normal force labelled as gravity. The force is selected and is blue with a visible force handle.

  1.  Select the intended force from the force type menu.

The intended force can be selected from the force menu in the free body diagram response area.

  1. The selected force arrow is updated to your selection in step 2.

The normal force is now properly labelled for the box on the incline.

Angle

To edit a drawn force's angle:

  1. Select the force arrow that you want to edit.

The normal force is drawn for a box on an incline but it's drawn at the wrong angle. The force arrow is selected and is blue with a visible force arrow handle.

  1. Click-and-drag the force's arrow handle to the intended angle.

The force's arrow handle was used to click-and-drag the arrow's angle to the correct angle for the normal force for the box on an incline.

NOTE: The force's angle field updates as you reposition the force arrow.

TIP: Alternatively, you can edit the force's angle by:

  1. Click on the force arrow that you want to edit.

The normal force is drawn for a box on an incline but it's drawn at the wrong angle.

  1. Edit the degree value that appears in the angle field for the selected force.

The incorrect angle of 94 degrees is shown in the angle field for the normal force of the box on an incline.

  1. Click outside of the response area.

The cursor is placed outside of the free body digram response area frame.

  1. The selected force arrow updates to the newly-defined angle.

The normal force is nowat the correct angle of 125 degrees which was entered in the angle field for the box on the incline.

Delete a drawn force

You can delete:

  • Individual forces
  • All drawn forces

Delete an individual force

To delete an individual force from the free body diagram response area:

  1. Select the force that you want to delete.

The static force is drawn incorrectly for a box on an incline. The force arrow is selected and is blue with a visible force arrow handle.

  1. Click Delete.

The Delete button appears in place of the "Draw" button when a drawn force is selected.

  1. The selected force is deleted from the response area.

Delete all drawn forces

To delete all drawn forces from the free body diagram response area:

  1. Click the hamburger menu of the response area.

The free body diagram menu is the first menu within the response area.

  1. Click Clear All.

The "Clear All" menu option is the last option of the free body diagram menu.

  1. Click Yes, clear all! to clear all drawn forces from the response area.

The "Clear All" confirmation modal states: Are you sure you wan to clear all forces? By doing so, all forces you have drawn will be deleted." The "Yes, clear all!" button is the first button in the modal.

TIP: Click No, thanks to cancel the deletion.

The "No, thanks" button is the second button in the Clear All confirmation modal.

  1. All drawn forces are deleted from the response area (if Yes, clear all! was selected at step 3).

 

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