Forces, Density And Pressure Flashcards
What is the center of gravity of an object?
The center of gravity of an object is the point at which the weight of the object may be considered to act.
What is a moment?
🔹A moment is a turning effect of a force.
🔻Depends on the perpendicular distance from the pivot to the line of action of the force.
What to do in a non-perpendicular force?
🔹consider the component of the distance which is perpendicular to the force.
The principle of moments states:
🔹For a system to be in equilibrium, the sum of clockwise moments about a pivot must be equal to the sum of anti-clockwise moments about the same pivot.
What is a couple?
🔹A couple is a pair of forces that act to produce rotation only.
🔻Depends on the perpendicular distance between the two forces.
The couple consists of a pair of forces that are:
🔹equal in magnitude
🔹opposite in direction
🔹Perpendicular to the distance between them.
Why doesn’t the object accelerate when a couple produces a torque?
🔹This is because a couple has a resultant force of zero. The pair of forces have a canceling effect.
What is a torque?
🔹The moment of a couple is a torque.
A system is in equilibrium when all the forces are balanced. This means:
🔹there is no resultant force
🔹there is no resultant torque
