Forces

• What is a vector?

  A vector has both magnitude and direction.
• What is a scalar?


  A scalar has just magnitude.
• Why can vectors be negative while scalars generally cannot?

  Vectors can be negative because they have direction, which can be defined as positive or negative.
• What is an example of a scalar quantity?

  Speed is a scalar quantity.
• What is an example of a vector quantity?

  Velocity is a vector quantity.
• What is the relationship between distance and displacement?

  Distance is a scalar, while displacement is a vector.
• What is the relationship between time and scalar/vector quantities?

  Time is a scalar quantity.
• What is acceleration classified as?


  Acceleration is a vector quantity.
• What is force classified as?

  Force is a vector quantity.
• What is mass classified as?

  Mass is a scalar quantity.
• What is momentum classified as?


  Momentum is a vector quantity.
• What is energy classified as?

  Energy is a scalar quantity.
• How does displacement change when a ball is thrown off a cliff?

  Displacement is 0 at the height of the cliff, positive above it, and negative below it.
• How can you define the "0" point of a vector in long answer questions?

  You can set the "0" point to be any reference point, such as the bottom of a cliff.
• What distinguishes speed from velocity?

  Speed is a scalar, while velocity includes direction.
• What happens to the velocity of a car traveling around a roundabout at constant speed?

  The velocity is constantly changing due to the change in direction, resulting in acceleration.
• How can vectors be visually represented?

  Vectors can be represented by arrows, with size/length indicating magnitude.
• What is a force?


  A force is a push or pull acting on an object due to interaction with another object.
• What are the two types of forces based on interaction?

  • Non-Contact Forces:
  • Electrostatic
  • Gravitational attraction
  • Contact Forces:
  • Normal contact force
  • Friction
• What is gravitational attraction?


  Gravitational attraction is the force created by mass that attracts other masses.
• What is the formula for weight?

  Weight is calculated as \( W = mg \).
• What does weight represent?

  Weight is the force exerted on a mass by the gravitational field.
• How is weight measured?

  Weight is measured by a force meter or calibrated spring-balance.
• What is the value of \( g \) on Earth?

  On Earth, \( g = 9.8 \, \text{m/s}^2 \).
• How does weight differ between two planets for the same person?

  The mass remains the same, but the gravitational field strength \( g \) differs, affecting weight.
• What is the acceleration in free fall due to gravity?

  The acceleration in free fall is \( 10 \, \text{m/s}^2 \).
• Where does the weight of an object act?

  The weight of an object acts at its center of mass.
• What is a resultant force?

  A resultant force is a single force representing the sum of all forces acting on an object.
• How do you find the resultant force when multiple forces act along a straight line?

  You can find the resultant by adding forces acting in the same direction and subtracting those acting in opposite directions.
• What are the forces acting on a skydiver during free fall?

  • Initially: Only weight acts on the skydiver.
  • As he falls: Air resistance increases, reducing the resultant force.
  • Eventually: Air resistance equals weight, resulting in no acceleration (terminal velocity).

  
• What is a free body diagram?

  A free body diagram shows the forces and their directions acting on an object.
• How can a force at an angle be resolved?


  A force at an angle can be resolved into components parallel and perpendicular to the ground.
• What is the formula for work done?


  Work done is calculated as \( W = F \times s \).
• What does work done represent?

  Work done represents energy transferred from the object doing the work to another form.
• What is the relationship between work done and energy when lifting an object?

  Work is done against gravity, increasing the object's gravitational potential energy.