mechanics Flashcards
what is a scalar quantity?
a quantity that has no direction.
what is a vetar quantity?
a quantity that has both direction and magnitude.
what are the two different ways of adding vectors?
scale drawings and using Pythagorus and trig.
how do you resolve a vector into horizontal components?
you draw a right angle that goes along the base of the vector and also goes up the hight and then you use trig to calculate their lengths. this is useful because the two components of a vector don’t affect each other meaning that you can deal with the two directions separately.
what happens if an object is in equilibrium?
the forces acting on it are balanced in each directions.
what does resolving forces mean?
it means splitting it into components. forces can be in any direction, so they are nit always at right angles to each other. you can think of it as tw separate forces, acting at right angles to each other. Fh = Fcosangle (horizontal component) and forFv = Fsinangle
what happens if the force that you are resolving is on a slope?
use sensible axis i.e. at right angles to the slant f the slope.
what is the principle of moments?
the sum of the clockwise moments is = to the sum of the anti clockwise moments when a body is in equilibrium.
what is meant by the centre of mass?
the point at which a single force on he boy has no turning effect. the single pointy in which the whole weight of n object acts through.
what is a couple?
a couple is a pair of forces of equal size that act in parallel with each other but in opposite directions.
the moment of a couple = the size of one of the forces x the perpendicular distance between the line of action of the forces.
