What is a scalar quantity?
A scalar quantity is a quantity that has a size or magnitude but no specific direction, e.g. mass
What is a vector quantity
A vector is a quantity that has a size or magnitude and a specific direction, e.g. weight ( acts downwards)
What is a resultant force
A resultant force is the net force acting; the single force that is equal to the
sum of all of the forces acting on the object.
What is a contact force?
A contact force is a force that must touch to interact with an object, e.g. friction, air resistance, stretching (tension)
What are non contact forces?
Forces that dont need to touch to interact with an object
What is the moment of a force?
The moment is the turning effect of a force. It occurs when a force causes an object to rotate around a fixed point called a pivot.
What is weight?
Weight is the force acting on an object due to gravity. The force of gravity close to the Earth is due to the gravitational field around the Earth.
The weight of an object depends on the gravitational field strength at the point where the object is.
How can you increase a moment?
1.Increase the magnitude of the force applied.
2.Increase the perpendicular distance from the pivot (e.g., using a longer spanner).
How does a lever make it easier to lift a heavy load?
A lever increases the distance from the pivot at which the force is applied. This means a smaller effort force can be used to create a large enough moment to move a heavy load.
How may a vector quantity be represented?
As an arrow, and the length of the arrow represents the magnitude, and the direction for the direction of the vector quantity. You will need to remember this for drawing parallelograms of forces.
What is the centre of mass?
The balance point of an object
