1.1 Basic Physics Flashcards
What is the SI unit of mass?
kg
What is the SI unit of length?
m
What is the SI unit of time?
s
What is the SI unit of electric current?
A
What is the SI unit of temperature?
K
What is the SI unit of amount of substance?
mol
What is the SI combination of volume?
m^3
What is the SI combination of density?
kg m^-3
What is the SI combination of velocity?
ms^-1
What is the SI combination of acceleration?
ms^-2
What is the SI combination of force?
kg ms^-2
What is a scalar?
A quantity with magnitude only
What is a vector?
A quantity with magnitude and direction
What is the resultant force is force n and force m act in the same direction?
n + m
What is the resultant force is force n and force m act in opposite directions
n - m
What is the resultant force is force n and force m act at right angles to each other?
root of n^2 + m^2
How do we find the direction of the resultant vector?
tan θ = opp/adj
How do we find the horizontal component of a force?
F cos θ
How do we find the vertical component of a force?
F sin θ
How is density defined?
Mass per unit volume
What is a moment?
Force times the perpendicular distance from the point to the line of action of the force.
What is the principle of moments?
The sum of anticlockwise moments about a point is equal to the sum of the clockwise moments about the same point
What is centre of gravity?
The point where all weight of an object is considered to act
In what direction does weight always act?
Vertically downwards (even if the object is on an angle)
What are the conditions for equilibrium?
- no resultant force in any direction
- no net movement about any point
