Forces Flashcards
What is a force?
A force is a push or pull, these are vector quantities. They are measured in Newtons (N) using a Newton Meter.
Contact forces
- friction
- air resistance (drag)
- upthrust
- buoyancy
- elastic
- water resistance
- thrust (driving force)
- lift
- tension
- reaction/normal force
Non-contact forces
- electrostatic
- magnetic
- weight (not gravity)
What is the normal force?
The normal force is the force between two surfaces to stop them passing through each other (eg. leaning on a wall, or standing on the floor).
Is gravity a force?
No, it is a concept.
Free body diagram rules
- draw arrows using a pencil and a ruler
- the head of the arrow shows the direction the force is acting in
- the size of the arrow shows the magnitude (size) of the force
- draw forces from the centre of the object, shown as a dot
Draw a free body force diagram of a dog running at a constant speed, labelling the forces.
N/a
Draw a free body force diagram of a car going up a ramp at a constant speed, labelling the forces.
N/a
What do balanced forces show?
Constant velocity
What do unbalanced forces show?
Acceleration
What is the resultant force?
The resultant force is the sum of all the forces acting on an object, it has both magnitude and direction.
How to find the resultant force?
- add the forces acting in the same direction
- take away the opposite forces
What is the resultant force of a balanced object?
0
What is the resultant force of a car driving 50N right and 60N left?
10N left
What is 1N equal to?
100g
