1. Basic physics Flashcards
What are the six base SI units?
kg, m, s, A, K, mol
State and give examples of scalar quantities.
A scalar quantity has magnitude only, such as mass, distance, speed and time.
State and give examples of vector quantities.
A vector quantity has both magnitude and direction such as displacement, velocity and acceleration.
What is the centre of gravity?
The point at which all the weight of the object is considered to act.
How does toppling occur?
When the weight force acts outside the base of the object.
What is the principle of moments?
If an object is in equilibrium, then the resultant moment about any pivot is zero.
What is a moment and its unit of measurement?
The product of force and the perpendicular distance between the line of action of the force and the pivot (M=Fxd) measured in Nm.
What is density and its unit of measurement?
The mass per unit volume (D=m/v) measured in kgm-3.
What is the general trend with density?
Solids have high density where gases have low density.
What is mass and it’s unit of measurement?
A measure of an objects inertia, measured in kg.
What is weight and it’s unit of measurement?
A measure of gratvity on an object, measured in N.
What is the percentage uncertainty?
Uncertainty/ value x100
What is the uncertainty of repeats?
Maximum-minimum/2
What are the two conditions that must be met if an object is in equilibrium?
The resultant force in any direction is zero
The net moment about any point is zero
How many seconds in an hour?
3600.
