Science - Force

  1. What is a force?
    This is something that can change the motion of an object
  2. State the SI unit for force
    The SI unit for force is the newton (N)
  3. How is force measured?
    Force is measured using a spring balance
  4. Explain what forces can do
    They can change the speed of an object

    They can change the shape and size of an object

    They can change the direction an object is moving in
  5. What is meant by contact forces?
    These are two objects that have to be in contact for these forces to occur eg. push, pull, friction and tension
  6. What is meant by non-contact forces?
    These are two objects that do not have to be in contact for these forces to occur eg. gravity
  7. Explain centre of gravity
    This is the point where the object balances
  8. What does an object need to have in order for it to be in stable equilibrium?
    A wide base

    A low centre of gravity
  9. What is meant by equilibrium?
    This is when all the forces are balanced in a body
  10. What is meant by stable?
    This is when an objects centre of gravity is inside the base of the object
  11. What is meant by unstable?
    This is when an objects centre of gravity is outside the base of the object
  12. What is meant by neutral?
    This is when an objects centre of gravity does not change
  13. What is a fulcrum?
    This is the turning point of an object
  14. What is a lever?
    This is any rigid body that rotates (free to move) about a fixed point called a fulcrum eg. see-saw
  15. Explain the law of the lever?
    This states that the sum of the clockwise moments equals the sum of the anticlockwise moments
  16. What is meant by a moment of a force?
    This is the rotation about the fulcrum
  17. Explain friction
    This is a force the opposes motion when two objects are place in contact
  18. State an advantage of friction
    It allows us to have grip when you walk, run and climb or when you alloy the brakes on a bike or in a car
  19. State a disadvantage of friction
    Wears away the soles of our shoes

    Wears away the tyres on our car and bicycles
  20. Explain how to reduce friction
    Lubrication is used to reduce the friction between two solids eg. oil and wax

    Surfers wax their surfboards to reduce the friction between the board and the water
  21. What are elastic objects?
    This is any object that is able to restore its shape after it has been stretched or compressed eg. springs and elastic bands
  22. What is meant by elastic limit?
    This is when elastic objects are extended to a point where they will not restore their shape
  23. Explain Hooke's Law
    This states that the extension of a spring is directly proportional to the applied force

    This is because the points give a straight line through the origin
Author
mshowley
ID
340438
Card Set
Science - Force
Description
Force
Updated