P8 2nd Flashcards
What do we mean by displacement
It is distance in a given direction
What is meant by a vector quantity
A physical quantity with direction and magnitude
What is meant by a scalar quantity
It has magnitude but no direction
How to represent a vector quantity
By an arrow in the direction of the vector and of length in proportion to the magnitude of the vector
What can forces do
They can change the shape of an object, or change its motion or its state of rest
What unit is there for force
Newton ( N )
What is a contact force
A force that acts on objects onlybwhen they touch each other
What are the forces being exerted when 2 objects interact
They always exert equal and opposite forces on each other
What is the resultant force
A single force that has the same effect as all the object acting on it
If the resultant forces of an object is :
- Zero
- Greater than Zero
- Zero , the object stays at rest or at the same speed and direction
- Greater than zero , the speed / direction of the object will change
1) If two forces act in the same direction the resultant force is their…
2) if oppisite directions …
1) Sum
2) Difference
What does the moment of a force measure
A measure of the turning effect of the force on the object
What is the moment of a force about a pivot
Perpindicular distance x force
What is a lever
A force multiplier that can be jsed to exert a force that is greater than the effort
What do gears do
They are used to change the moment of a turning effect
