Chapter 4: Mechanics Flashcards
What is a scalar?
a quantity that has magnitude but no direction
What is a vector?
a quantity that has magnitude and direction
What are some examples of scalars?
distance, speed, energy, mass, power, temperature
What are some examples of vectors?
displacement, velocity, force (inc. W), acceleration, momentum, electric/magnetic field
To resolve vectors, they should be placed ……….
tip-to-tail
When resolving vectors, they should be split into…..
a horizontal and vertical component
Parallel vectors of equal magnitude are …..
equivalent
What does it mean if an object is in equilibrium?
all forces acting on it are balanced
there is no resultant force
an object in equilibrium can be at rest or at constant VELOCITY
What is mass?
the amount of matter in an object
measured in kg
it does not change as the strength of the gravitational field changes
What is weight?
it is a force
measured in Newtons (N)
it is the force experienced by mass due to a gravitational field, weight does vary according to the size of the gravitational field
What is the formula for weight?
W=m*g
g= gravitational field strength (Nkg⁻¹)
What is a moment?
- the turning effect of a force around a pivot
- depends on the force applied from the pivot and the distance from the pivot
What is the principle of moments?
for a body to be in equilibrium, the sum of the clockwise moments about any point equals to the sum of the anticlockwise moments around the same point
if the moments aren’t balanced, the object will turn
What is a lever?
a structure made of a rigid object rotating around a pivot, in which an effort force works against a load force
they increase the distance from a pivot so less force required to get the same moment
What is a couple?
a pair of forces of equal size which act parallel to each other but in opposite directions, doesn’t cause a resultant linear force, but does produce a moment
