dynamics Flashcards
(16 cards)
what is newton’s first law
an object will remain stationary or moving in constant velocity unless a resultant force acts on it
define newton’s second law
the acceleration of an object is proportional to the resultant force acting on it and inversely proportional to the object’s mass F=ma
define newton’s third law
every force has a counter force equal in magnitude but opposite in direction (the force must be of the same kind, but acting on another object)
define force
the rate of change of momentum
define mass
the property of an object that resist change in motion
define linear momentum
the produce of mass and veloctiy
what increases friction and air-resistance
speed
describe motion of free fall with air-resistance
initially acceleration max, velocity mini. drag mini
speed increase, drag increase
reacher terminal velocity, acceleration zero, drag=weight
principle of conservation of momentum
the sum linear momentum in any given direction is constant within a closed system
what is elastic collision
- all kinetic energy is conserved
- relative speed of approach is equal to relative speed of separation
- if the objects stick together after collision then definitely inelastic
what is centre of gravity
the conventional point of an object where all weight is thought to be act on
define moment of force
the turning effect, which is the product of force and perpendicular distance from the pivot
moment equation
τ = F * d * sinçç
equation for momentum
p = m v
impulse of force
F t = ∆p
inclined slope
weight parallel to the slope = W * sinθ
weight perpendicular to the slope (contact force) = W * cosθ
W=actually weight
