Physics P5 Key Knowledge
Terms in this set (15)
Forces ( vector quantities )
An interaction between 2 objects. Have a size (magnitude) and direction, like velocity. Can be a push or a pull
Examples of vectors ( forces )
Force, displacement, acceleration, momentum.
Have no direction like speed
Examples of scalar quantities
Speed, distance, mass, temperature, time
When 2 objects are touching each other, e.g. friction, air resistance, tension, normal contact force.
A force between 2 objects that don't touch, e.g. magnetic force, gravitational force, electrostatic force.
Caused by gravity pulling on an object's mass. As mass increases, weight increases - they are directly proportional.
mass x gravitational field strength
(kg) x (N/kg)
When 2 objects interact a force acts on both objects. The forces are equal in size and opposite in direction. Remember they are on different objects (e.g. the ground and your foot)
Free body diagram
Shows the forces acting on an isolated object, using arrows for forces. The size of the arrow shows the magnitude of the force.
Overall force acting on an object. It acts to change the speed, direction or shape of the object.
The same as energy transferred
This is the result of a force moving an object, so energy has been transferred from one store to another.
Work done = Force x Distance
(J) = (N) x (m)
When two forces act on an object and change its shape permanently.
When two forces act on an object and change its shape, but the object returns to its original shape.
When an object can be stretched, bent or compressed. More than one force is needed to do this because otherwise the object would move.
The extension of an elastic object (such as a spring) is
to the force....
.... until the *limit of proportionality is reached.