Resultant forces

• What is meant by a resultant force?

  A single force representing multiple forces
• How do you calculate the resultant of forces acting in a straight line?

  Subtract the smaller force from the larger force
• What is a Freebody diagram used for?

  To show forces acting on an object
• What is a force?

  A push or pull acting on an object
• Why are forces considered vector quantities?

  They have both magnitude and direction
• If a man pushes a box with 20 Newtons right and friction is 10 Newtons left, what is the resultant force?

  10 Newtons acting to the right
• How do you find the resultant force when multiple forces act in different directions?

  Calculate total forces in each direction
• What is the resultant force on a car with a driving force of 10,000 Newtons left and friction of 4,000 Newtons right plus air resistance of 5,000 Newtons right?

  1,000 Newtons acting to the left
• What does it mean when forces are balanced?

  The resultant force is zero
• What does a Freebody diagram represent?

  Forces acting on an object as arrows
• What does the length of the arrow in a Freebody diagram indicate?

  The size of the force
• What is lift in the context of an airplane?

  A force acting upwards against weight
• What forces act on an airplane flying at constant altitude?

  Weight, lift, thrust, and drag
• Why must the forward and backward forces on an airplane be balanced?

  To maintain constant velocity
• What is the force of air resistance acting on the airplane?

  It acts in the reverse direction
• What are the steps to draw a Freebody diagram?

  • Represent the object as a point
  • Draw forces as arrows starting from the point
  • Ensure arrow length shows force size
  • Ensure arrow direction shows force direction
• What are the forces acting on a skydiver at constant velocity?

  • Weight: 800 Newtons downwards
  • Air resistance: 800 Newtons upwards
  • Resultant force: Zero (balanced forces)
• What are the forces acting on an airplane flying at constant altitude?

  • Weight: acting downwards
  • Lift: acting upwards
  • Thrust: acting forwards
  • Drag: acting backwards
• What is the relationship between thrust and drag for an airplane at constant velocity?

  • Thrust equals drag
  • Forces are balanced
  • No acceleration occurs
• What can you calculate using vector diagrams?

  The resultant of two forces at an angle
• What is the term for a single force that replaces multiple forces?

  Resultant force
• What is the first step in calculating the resultant force at an angle?

  Make a scale drawing of the forces
• If 1 cm equals 1 Newton, how long should the arrow be for a 10 Newton force?

  10 cm
• What shape is created to find the resultant force from two vectors?

  Parallelogram
• How is the resultant force calculated from the vector length?

  By converting cm to Newtons
• If 1 cm equals 40 Newtons, how long should the arrow be for a 280 Newton force?

  7 cm
• What are the steps to calculate the resultant force using vector diagrams?

  1. Make a scale drawing of the forces.
  2. Draw arrows to represent each force.
  3. Measure the angle between the forces.
  4. Create a parallelogram using the vectors.
  5. Measure the resultant vector length.
  6. Convert the length to Newtons.
• How does the resultant force change if the angle between two forces increases?

  It may increase or decrease