Forces Flashcards
What is Hooke’s Law?
If the limit of proportionality is not exceeded, the extension produced in a material is directly proportional to the force/ load applied
EPE?
Area under the F-x graph (1/2Fx=1/2kx^2)
What is upthrust?
Upward force exerted by fluid on a submerged or floating object, and arises because of the difference in pressure between upper and lower surfaces of object.
What is Archimedes’ Principle
Upthrust = Weight of fluid displaced by submerged object Upthrust = Vsubmerged x Pfluid x g
Formula for hydrostatic pressure
p=density x g x h
Viscous Force?
Force that opposes motion of object in fluid, magnitude increases with speed of object
What is moment of a force?
Product of the force and the perpendicular distance of its line of action from the axis of rotation
What is torque of a couple?
Product of one of the forces of the couple and the perpendicular distance between the lines of action of the forces.
What is a couple?
A pair of equal and opposite forces, whose line of action do not coincide.
Conditions for Equilibrium?
Resultant force acting in any direction is zero and the resultant moment abut any axis is equal to zero.
Principle of Moments
When a body is in equilibrium, the sum of all anticlockwise moments about any point is equal to the sum of all the clockwise moments about the same point.
Centre of Gravity?
A single point through which the entire weight of the object may be considered to act.
If mass acted on by three forces and in equilibrium, what are the conditions?
Lines of action of the forces pass through common point, and vector diagram forms closed triangle with vectors pointing in same orientation.
