Study

Mass & Weight

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  • What is air resistance? Give an example where it is useful.
    Air resistance is a kind of friction which occurs between air and another object. It is useful to parachutists who use it to slow down their fall.
  • Describe Neton's 2nd law. Give an example.
    The greater the mass of an object, the greater the force required to move it. e.g. more force is required to accelerate an elephant than a mouse.
  • Are the forces balanced or unbalanced?
    Balanced
  • Balanced or unbalanced?
    Unbalanced
  • Describe the difference between mass and weight.
    Mass is a measurement of how much matter or "stuff" is in an object. Weight is a measurement of the gravity acting on the object.
  • Give two examples of a non contact force.
    Magnetism and gravity.
  • Where will an astronaut have a greater mass? On the moon or on earth?
    None: Mass stays the same, it is not affected by gravity.
  • What is upthrust? What keeps it balanced?
    The upward force that a liquid puts on an object floating in it. The weight of the object balances the upthrust.
  • Describe Newton's third law. Give an example.
    Every action has an equal and opposite reaction. e.g. stepping off a boat and the boat pushes back or a rocket pushing air down so that it goes up.
  • Who discovered gravity and how?
    Isaac Newton discovered gravity when he saw an apple fall straight down from a tree and wondered why it didn't fall sideways or upwards.
  • Using Weight = Mass x Gravitational field, calculate the weight of a 75kg object on Uranus. (Uranus GFS = 9N/KG)
    675N
  • What is net/resultant force? What does it show us?
    Net or resultant force is the sum of all the forces acting on an object. It shows us whether the object will accelerate in any direction or remain still.
  • How does surface area affect air resistance?
    The greater the surface area, the greater the air resistance.
  • Balanced or unbalanced?
    Balanced
  • Using Weight = Mass x Gravitational field, calculate the weight of a 50kg person on the moon. (Moon GFS = 1.6N/KG)
    80N
  • What factors can affect the friction on an object?
    The surface (rough or smooth), the weight (heavy or light), surface area
  • Are the forces balanced or unbalanced?
    Unbalanced. It will move to the left.
  • Which direction will the people move? Why?
    They will move to the left because the force is unbalanced.
  • What is friction?
    Friction is a force that resists the sliding or rolling of one solid object over another.
  • What are mass and weight measured in? Give an answer for each.
    Mass in KG, Weight in Newtons
  • What is Newton's first law? Give an example to support your answer.
    An object will not change its motion unless a force acts on it (object in rest will stay at rest) e.g people flying forward when a car stops quickly.