Changing shapes

• Forces can affect bodies in various ways:

  • Changes in speed: forces can cause bodies to speed up or slow down
  • Changes in direction: forces can cause bodies to change their direction of travel
  • Changes in shape: forces can cause bodies to stretch, compress, or deform
• Types of forces include:

  • Gravitational (or weight) force
  • Electrostatic force
  • Thrust force
  • Upthrust force
  • Air resistance (or drag) force
  • Compression force
  • Tension force
  • Reaction force
• Scalars are quantities with only magnitude, while vectors have both magnitude and direction

  • Examples of scalar quantities: mass
  • Examples of vector quantities: velocity, displacement
• Force is a vector quantity because it describes both magnitude and direction

  • Resultant force is a single force that describes all forces acting on a body
  • Resultant forces can be calculated by adding or subtracting all forces acting on the object
  • Balanced forces cancel each other out, resulting in no resultant force
  • Unbalanced forces do not cancel out completely, leading to a resultant force on the object
• Friction is the force that opposes the motion of an object

  • Frictional forces act in the opposite direction to the object's motion
• Unbalanced forces on an object result in a resultant force that causes acceleration
• Resultant force causes the object to speed up, slow down, or change direction
• The relationship between resultant force, mass, and acceleration is given by the equation: F = m × a
• Weight is defined as the force acting on an object due to gravitational attraction
• Weight and mass are related by the equation: W = m × g, where g is the acceleration due to gravity
• Stopping distance of a car is the total distance traveled during the time it takes for the car to stop in response to an emergency
• Stopping distance = Thinking distance + Braking distance
• Factors affecting stopping distance include vehicle speed, vehicle mass, road conditions, and driver reaction time
• Falling objects experience two forces: weight (due to gravity) and air resistance (due to friction)
• Terminal velocity is reached when air resistance equals weight, resulting in balanced forces and zero acceleration
• The weight of an object is the force of gravity which acts on it
• When something falls, initially it accelerates
• The faster it falls, the larger the force of friction which acts on it
• Eventually it falls at a steady speed when the force of friction equals the force of gravity acting on it
• A cylinder has two circular bases, joined together with a curved side.