Forces

• Gravitational Force


  Gravity is a force of attraction between all objects. Gravity attracts all masses, but you notice it if one or more of the masses are big.
• Weight and Mass


  The mass of an object tells us how much matter the object has in it. The mass of an object does not depend where the object is.
• The weight of an object is the force acting on it due to gravity. The unit for weight is newtons (N). The weight of an object depend on where the object is.
• The Gravitational Field Strength is a measure of the force of gravity in a particular location. This means that the weight of an object changes with its location. An object has the same mass whether it's on the moon or the earth- but the weight is different. In addition, the weight of an object is directly proportional to the mass of the object. This means that if the mass is doubled then the weight is also doubled.
• We can determine an object's mass by using a calibrated spring constant, also known as a Newton meter. The weight of an object can be considered to act as a single point. Scientists call this pint the centre of mass- The point where all of the mass of an object is concentrated.
• Scalar Quantities

  Scalar- Scalar quantities have magnitude (size) only. (E.g. Mass, Energy, Speed and distance)
• Vector Quantities

  Vector- Vector quantities have both magnitude and direction. (E.g. Force, Velocity and Density). The length of the arrow represents the length of the vector. The direction of the arrow represents the direction of the vector.
• What is a force?

  A force is a push or a pull that acts on an object due to its interaction with another object. All forces have both magnitude and direction. A force is measured in Newton's (N).
• Contact force

  A contact force is when two objects are physically touching. (E.g.Tension, Friction, Air resistance and normal contact force)
• Non-contacts force

  A non-contact force is when two objects are physically separated. (E.g. Gravitational, Electrostatic and Magnetic forces).