Force & Acceleration

Physics: Cambridge International GCSE Supplement, topic 1.5.3

Force and Acceleration

A force may cause a mass to accelerate. This acceleration can be a change in speed, a change in direction or a change in both speed and direction.

Resultant force

Resultant force

  • The resultant force is the sum of all of the forces acting on an object.
  • The change in an object’s motion is caused by the resultant force.
  • If the forces acting on an object are unbalanced (not equal) it means that a resultant force is acting on the object.
  • The resultant force and acceleration act in the same direction.
Resultant force equation

Resultant force equation

  • A resultant force causes an acceleration.
  • The acceleration can be calculated with this equation.
  • Resultant force (F) = mass (m) x acceleration (a).
  • This is Newton's 2nd Law.

Test yourself on Force & Acceleration

  • Which of the following are true?

  • What will happen to a moving object if there is no resultant force?

  • Which of these statements about acceleration are correct?

  • What does a resultant force cause in an object's motion?

  • If an object has a weight of 10 N and there are other forces acting on the object, will the object accelerate? Do we need more information?

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