Chapter 8

• What is force defined as?

  Force is a pull or a push upon an object.
• What type of quantity is force?

  Force is a vector quantity that has magnitude and direction.
• What is the S.I. unit for force?

  The S.I. unit for force is Newton (N).
• What does Newton's Third Law state?

  Newton's Third Law states that for every action force, there is a reaction force of the same magnitude but in the opposite direction.
• What are the types of forces mentioned?

  • Gravitational force
  • Normal force
  • Weight
  • Buoyant force
  • Frictional force
  • Elastic force
• What is gravitational force?


  Gravitational force is the force of attraction between two masses.
• What is normal force?

  Normal force is the support force exerted upon an object that is in contact with another stable object.
• What is weight?


  Weight is the force exerted by gravity on an object.
• What is buoyant force?

  Buoyant force is the upward force exerted by a fluid on an object immersed in it.
• What is frictional force?

  Frictional force is the force that opposes the relative motion of two surfaces in contact.
• What is elastic force?

  Elastic force is the force exerted by a material when it is stretched or compressed.
• What can force change in an object?

  Shape, size, and motion
• What are the effects of force on a stationary object?

  It can move the object.
• What happens when a force is applied to a moving object?

  It can stop the object or change its speed or direction.
• How does force affect the shape and size of an object?

  Force can change the shape and size of the object.
• What is the formula for buoyant force?

  Buoyant force = Actual weight - Apparent weight
• How does the density of an object affect its buoyant force?

  The denser the object, the lesser the buoyant force, causing it to submerge.
• What happens to less dense objects in terms of buoyant force?

  They experience a higher buoyant force and float.
• What is a lever?


  A lever is a bar that rotates on a fixed point.
• What are the three parts of a lever?

  Effort, load, and fulcrum.
• What are the classifications of levers?

  • First class lever: Fulcrum is between load and effort.
  • Second class lever: Load is between fulcrum and effort.
  • Third class lever: Effort is between fulcrum and load.
• What is the moment of force?

  It is the turning effect produced by a force acting on an object at a fixed point.
• What is the formula for moment of force?


  Moment of force = Force (N) x Perpendicular distance from the pivot (m)
• How is pressure defined?

  Pressure is defined as force per unit area.
• What is the S.I. unit for pressure?

  Pascal (Pa)
• What is the formula for pressure?

  Pressure = Force (N) / Surface area (\(\text{m}^2\))
• What produces air pressure?


  The frequency of collision between air molecules and the walls of a container.
• What factors affect gas pressure?

  • Volume
  • Temperature
  • Atmospheric Pressure
• What is atmospheric pressure?


  It is the pressure exerted by the atmosphere on the surface of the Earth and all objects on it.
• What are some applications of air pressure in daily life?

  • Plunger
  • Magdeburg Hemisphere
  • Straw
  • Syphon
  • Syringe
  • Vacuum cleaner
• How does atmospheric pressure change with altitude?

  Atmospheric pressure decreases as altitude increases.
• What are examples of the effects of depth on liquid pressure?

  • The walls of a dam are thicker at the base to withstand high water pressure.
  • A diver wears a special suit to withstand high water pressure.