Free Body Diagrams & Forces

• What is the value of the normal force (F_N) acting on the 10kg object?

  98N
• What forces are acting on the 10 kg mass in the free body diagram?

  • Gravity (downward)
  • Normal force (upward)
  • Applied force (right)
  • Friction (left)
• Why is the frictional force (F_f) negative?


  The frictional force is negative because it opposes the direction of motion.
• What should you draw first when creating a free body diagram?

  A dot or shape to represent the object
• If an object is on a ramp, what force would be acting on it?

  Force of ramp (F_r)
• What is the purpose of a free body diagram?

  To show all the forces acting on an object
• What does a free body diagram illustrate?

  All forces acting on an object
• Why is it important to identify all forces acting on an object in an FBD?

  To accurately represent the object's interactions
• How would the free body diagram change if the object was moving up the ramp instead of down?

  The direction of the force of ramp (F_r) would be reversed
• In a free body diagram, how is each force represented?

  As an arrow pointing in its direction
• What are the different types of forces shown in the free body diagram?

  • Normal force (N)
  • Friction force (F_f)
  • Gravitational force (F_g)
  • Applied force (F_applied)
  • Force of air (F_air)
  • Force of ramp (F_r)
• Why is it important to resolve vectors when calculating resultant force?

  To break down oblique forces into components
• What is the resultant force when $F_{1} =$$30\,\text{N} uparrow$ and $F_{2} =$$40\,\text{N} rightarrow$?


  50 N at approximately 36.87°
• How is the resultant force calculated when two forces are acting on an object?

  By adding the magnitudes of the forces
• What must each arrow in a free body diagram be labeled with?

  Force name and magnitude
• What is the title of the image?

  How to Draw Free Body Diagrams
• What is a free body diagram?

  A diagram showing forces on an object
• What are the key steps to draw a free body diagram?

  1. Identify the object of interest
  2. Draw the object as a simple shape
  3. Identify all the forces acting on the object
  4. Draw each force as an arrow with the correct magnitude and direction
  5. Label each force with its appropriate symbol
• What are the steps to calculate resultant force?

  1. Identify forces with magnitudes and directions
  2. Resolve vectors into horizontal and vertical components
  3. Add components separately
  4. Calculate magnitude using Pythagorean theorem
  5. Determine direction using trigonometry
• How do you determine the direction of the resultant force?

  Use trigonometry to find the direction
• What are the steps to calculate resultant force for forces in the same line?

  1. Identify forces acting in the same direction.
  2. Add the magnitudes of the forces.
  3. State the resultant force and direction.
• What does friction do in free body diagrams?

  Resists motion as a contact force
• What are the steps to calculate resultant force for perpendicular forces?

  1. Identify the perpendicular forces.
  2. Use the Pythagorean theorem to calculate total force.
  3. Determine the direction using the tangent function.
  4. State the resultant force and its direction.
• Why is the normal force (F_N) equal to -F_G?

  Because the normal force is a reactionary force that opposes the gravitational force (F_G)
• What are the types of forces mentioned in resultant force calculations?

  • Forces in the same line
  • Perpendicular forces
• What occurs when you and your friend pull in different directions?

  • You pull up with 3 balloons
  • Your friend pulls to the side with 4 balloons
  • A triangle is formed to determine the resultant force direction
• Why must forces balance in free body diagrams?

  To keep an object stationary
• What is the normal force in free body diagrams?

  Contact force pushing perpendicular to surface
• What is the first step to calculate resultant force?

  Identify forces acting on the object
• How are the forces shown in the free body diagram related to each other?

  • Forces are shown as vectors with magnitudes and directions
  • Forces can be added/subtracted using vector addition
  • The net force determines the acceleration of the object
• What theorem is used to calculate the magnitude of the resultant force?

  Pythagorean theorem
• How do you sum the components of forces?

  Add horizontal and vertical components separately
• What is the angle $θ$ when $tan(θ) =$$\frac{30}{40}$?


  $36.87°$
• What is the purpose of free body diagrams (FBDs)?

  To identify common forces acting on objects
• What is the value of the applied force (F_a) acting on the 10kg object?

  1000N
• What is the formula for calculating the total force when two forces are acting on an object?

  $\vec{F}_{total} =$$\vec{F}_{1} +$$\vec{F}_{2}$
• What are the forces acting on block A?

  • Weight of block A (W_A)
  • Normal force exerted by B on A (N_BA)
  • Friction force exerted by B on A (f_BA)
  • Tension (T)
• If $F_{1} =$$20\,\text{N}$ and $F_{2} =$$30\,\text{N}$, what is the total force?


  $50\,\text{N}$
• If $F_{1} =$$30\,\text{N} \uparrow$ and $F_{2} =$$40\,\text{N} \rightarrow$, what is the total force using the Pythagorean theorem?


  $50\,\text{N}$
• What does the resultant force determine for an object?

  It determines the object's overall acceleration