Forces Flashcards
Define physical quantity
A physical quantity is a physical property of a phenomenon, body, or substance, which
can be quantified by measurement.
Quantity symbol of time
t
Quantity symbol of mass
m
Quantity symbol of force
F
Quantity symbol of weight
Fg
Quantity symbol of charge
Q
Si unit for seconds (t)
s
Si unit for kilograms (m)
kg
Si unit for newton (F)
N
Si unit for newton (Fg)
N
Si unit for coulomb (Q)
C
What two groups are classified as physical quantities
Scalar quantities
Vector quantities
Define Scalar quantity
A scalar quantity is a physical quantity that has
magnitude (size) only.
What does scalar quantity include?
Mass, electric charge, time, distance (MEDT) scales of fish
Define vector quantity
A vector quantity is a physical quantity that has
magnitude and direction.
What does vector quantity include?
Force, weight, velocity, acceleration (WAVF)
What are the two ways of describing direction?
Relative direction and compass points
What is relative direction?
up, down, left, right, forwards, backwards
What is compass points?
North, east, south, west
How is a vector shown?
arrow pointing to the right written above it
When is arrow left out of vector?
If the magnitude (size) of a vector is only needed, then the arrow is omitted (left out).
How are vectors graphically represented?
Arrow defining the direction, and the length of
the arrow defines the vector’s magnitude according to a scale.
How are two vectors equal?
Equal if they have the same magnitude and direction,
regardless of whether they have the same initial points,
Define forces
A force is a push or a pull that acts in a certain
direction.
What two things do forces have?
Magnitude (size) and direction
What can forces change?
Change a body’s state of motion in a straight line.
How can forces be measured?
spring scale/spring balance/newton meter (
What spring scales include?
Spring connected to a metal hook
When does the spring stretch (balance)?
Force is applied to hook
When does the spring stretch long?
The bigger the force applied, the longer
the spring stretches and the higher the reading.
When describing a force, which of the following 4 points must be noted?
exerting the force
experiencing the force
magnitude of the force
direction force is being exerted
What does the length of the arrow represent?
Represents the magnitude of the force
What does the arrowhead represent?
arrowhead represents the direction of the force.
How can we also describe the direction in which a force acts?
cardinal points system
What are free body diagrams are used to represent?
Free body diagrams are used to represent all of the forces acting on an object graphically.
What happens when more than one force can act on an object at a time?
Multiple arrows connected to the same dot.
If the forces are acting in the same direction, what do you do?
Draw separate arrows, connected to
the same dot
How does one represent force?
uppercase ‘F’ to show that it is a force,
subscript to show who or what is exerting the force.
What are the effects of forces?
Forces do not always have an effect, but the effects that they can have are the following.
Name the four effects of forces
Motion, distortion, direction, rotation
What is motion?
change the speed of an object.
cause a stationary object to move.
cause a moving object to stop.
What is distortion?
change the shape of an object.
Elastic objects return to their original shape - force removed.
Inelastic objects are permanently distorted.
What is direction?
A force can change the direction in which
something is moving.
What is rotation?
A force can cause an object to spin.
Define balanced and unbalanced forces
The resultant force (Fnet) is the single force which
has the same effect as the original forces acting
together.
What is another word for Fnet?
Resultant force
Fnet = 0
Balanced force
Fnet = 0 not
Unbalanced force