Forces

• Contact forces are when two objects touch each other.
• Forces can be contact forces (pushing against something) or non-contact forces (pulling on something).
• A force is any push or pull that changes the speed, direction or shape of an object.
• The moment of a force depends on the size of the force and where the force is applied. The greater the force and the further it is applied from the pivot the greater the moment. The distance between. The force and the pivot is measured at right angles to the direction of the force.
• A turning force is called a moment.
• Total clockwise moment=total anti-clockwise moment
• Gears can be used to transmit the rotational effect of forces. Gears are sets of wheels with interlocking teeth.
• A lever is a simple machine that consists of a long bar and a pivot. It can increase the size of a force or increase the distance the force moves.
• Work done is the energy transferred by a force through a distance
• Power is the amount of energy transferred every second
• Energy is something that is needed to make things happen or change
• The axis around an object is known as a pivot
• When a force acts on an object, it causes work to be done
• A vector is a quantity that has both magnitude (size) and direction
• A scalar is a quantity with only size but no direction
• All the forces acting on an object is known as a resultant force
• Upthrust is the upwards force on an object in water
• Thrust is the downwards force on an object in water
• Power is equal to workdone over time taken
• Work done is equal ro force times distance
• Force field is the space around an object
• Resolving a force means 'splitting' up a force into two component forces at right angles to eachother
• The overall affect of the two component forces is the same as the affect of the original force
• Finding a resultant force means working out a single force that has the same affect as the other forces acting on the same object
• A free body diagram uses labelled arrows to show all the forces acting on the object.

  -The direction of each arrow show the direction of the force.

  -The length of the arrow shows the size of the force.
• Kinetic energy is equal to 1/2 × mass × velocity²
• Kinetic energy is the energy an object possesses due to its motion
• Gravitational potential energy is the energy an object possesses due To its position in a gravitational field. It is directly proportional to the height of the object above a reference
• Gpe is equal to mass × G × ■h

  (■ = Delta change )
• A turning force is called a moment and depends on the size of the force and where the force is applied