Flashcards in Forces in Equilibrium Deck (11):
What is the difference between a vector and a scalar?
A vector is any physical quantity that has a direction and a magnitude. Where as a scalar is any physical quantity that is not directional.
What is the principle of moments?
An object is in equilibrium when..
the sum of the clockwise moments = the sum of the anticlockwise moments
For a triangle where P is the hypotenuse, and Y is the angle between P and the adjacent (A), how would you calculate the size of the adjacent (A)?
For a stationary object the resultant force is...
If two forces are acting perpendicular to each other, how can you find the magnitude of the resultant force?
Pythagoras' theorem [A^2+B^2=C^2]
How do you calculate the moment of a force?
Force x Perpendicular distance from the point of action.
What is a moment?
The turning effect of a force
What are the units for a moment?
What is the difference between stable and unstable equilibrium?
An object is in stable equilibrium if it can be displaced, and it will return to its original position.
[eg. a ball on a string]
An object is in unstable equilibrium if it can be displaced, but will not return to its original position.
[eg. a plank resting on a round ball]
What is the resultant force for an object moving at a constant velocity?