Chapter 4 Flashcards
What is a MOMENT?
A moment is the turning effect of a force.
What is a PIVOT?
A pivot is the point that does not move by rotation.
Finish:
When an object is in ___ , the sum of the _____ is ____ to the sum of the _________
When an object is in balance, the sum of the clockwise moments is equal to the sum of the anticlockwise moments.
What is the equation for a MOMENT?
Moment = Force × Distance (Perpendicular distance from the pivot)
What is MASS?
Mass is the amount of matter in an object.
Mass is constant.
What is WEIGHT?
Weight is the downward force on an object due to gravity.
Weight vaires with acceleration due to gravity (g).
What is meant by THE CENTRE OF MASS?
The point through which any externally applied force produces straight-line motion but no rotation.
What is meant by THE CENTRE OF GRAVITY?
The point through which an object’s weight appears to act.
What is the equation for PRESSURE and what is its UNIT?
Presser = Force ÷ Area
P = F ÷ A
Pressure is measured in Nm² or Pa
What is the equation for DENSITY?
Density = Mass ÷ Volume
ρ = m ÷ V
ρ = kgms-³ (kgms to the -3)
What is UPTHRUST?
The upthrust is the difference between the upper surface force and the lower surface force
What is the equation for UPTHRUST?
(h+x)ρAg - ρhAg =xρAg
State ARCHIMEDE’S PRINCIPLE
The upthrust exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the object displaces.
