Chapter 3: Forces Flashcards
What is Hooke’s law?
The change in length of a material is directly proportional to the applied force (F = kx) provided that the limit of proportionality is not exceeded.
What is the formula for fluid pressure at depth h in a fluid of density p?
P = hpg
Total pressure = P₀ + hpg, where P₀ is the atmospheric pressure
What is upthrust?
The upward force exerted by the fluid on an object fully or partially submerged in the fluid due to the difference in pressure on the upper and lower surfaces of the object
(it is equal in magnitude and opposite in direction to the weight of the FLUID displaced)
What is moment of a force?
The product of the force and the perpendicular distance of the point from the line of action of the force
What is the torque of a couple?
The product of one of the forces and the perpendicular distance between the forces
What does it mean when a body is in equilbrium?
When the resultant force and the resultant torque of the body are both zero
State the principle of moments
When a body is in equilibrium, the sum of clockwise moments about a point is equal to the sum of anticlockwise moments about the same point
What is a couple?
A pair of forces of equal magnitude but acting in opposite directions and whose lines of action are parallel and separate.
Origin of Upthrust
Pressure increase with depth in a fluid, causing pressure acting upwards to outweigh pressure acting downwards on the body
