Flashcards in P8 - Forces Deck (17)
Something with magnitude and direction.
- eg. Momentum, acceleration, force, gravitational field strength.
With magnitude but no direction.
-eg. Mass, speed, time, mass, energy.
Distance given direction.
Newtons 3rd law?
When two objects interact with each other, they excert equal and opposite forces on each other.
Newtons 1st law?
When forces are balanced, the rf is 0 and the object will remain in constant motion or remain stationary.
D. Centre of mass?
The point at which the mass of an object is thought to be concentrated
What happens when an item is suspended?
It will come to rest with its centre of gravity directly below the point of suspension
Centre of mass of a uniform ruler?
Centre of mass of a symmetrical object?
Along the axis of symmetry (if more then one, where they cross)
What happens to a freely suspended object when a turning force is removed?
it returns to equilibrium
D. Contact force?
A force that only acts on objects when they touch each other
How many objects do free-body force diagrams show?
Low gear gives...
Low speed and high turning effect
High gear gives...
High speed and low turning effect
Gears are used to...
Change the moment of a turning effect
If an object at rest doesn't turn....
the sum of all clockwise moments about any point = sum of all anticlockwise moments about any point