Quiz #1 Flashcards
Newton’s 1st Law
If an object is in motion, it will remain in motion. If an object is at rest, it will remain at rest, unless a force acts on it
Newton’s 2nd Law
When the sum of forces acting on an object is nonzero, the sum of the forces equals the product of the mass and its acceleration. F=ma
Newton’s 3rd Law
For every reaction, there is an equal and opposite reaction.
Particle
Is a mathematical model of an object as a mass point. i.e. A particle has mass but no size (dimensions) or shape
Object as a mass point.
Gravity (g)
9.81 m/s^2 OR 32.2 ft/s^2
Mass
Scalar Quantity
Mass
Amount of material in body
Mass
Measure of Inertia
a.) Inertia is the measure of the resistance to a change in motion.
Mass
Same in any gravitational field
a.) independent of location
Mass
Units: a) Slugs b) Kilograms
1 Slug = 14.59 kg
Weight
Vector quantity
Weight
Effect of gravity on a body
Weight
Measure of the force exerted on a body by a gravitational field
Weight
Varies with the strength of gravitational pull
a) dependent on location
Weight
Units: a) Pounds b) Newtons
1lb = 4.448N
Rigid Body
A mathematical model of a material body or a system of particles in which the distance between any two particles remains constant. i.e. NO DEFORMATION
“Material body or system of particles w/ NO DEFORMATION”
Scalar
A quantity that can be completely specified without mentioning a direction.
Time, temperature, volume, mass, or energy speed, distance
Only magnitude
Vector
A quantity (directed line segment) is completely specified by mentioning magnitude and direction, and it is added according to the parallelogram law.
Displacement, velocity, acceleration, momentum, or force
Includes magnitude and direction
Magnitude
Length of a vector
Free Vector
Has a definite magnitude and direction but no specific location in space
Sliding Vector
one which can be moved along a given line collinear with the vector itself
Bound Vector
One with a specified point of application
Characteristics of Force
1) Point of application
2) its magnitude
3) its direction
a) Defined by the line of action and the sense of the force\
b) Line of Action is the infinite straight line along which
the force acts.
Concentrated Force (Load)
represents the effect of loading which is assumed to act at a point on a body
Distributed Load
is a force or force system spread over an area, either uniformly or non-uniformly
External Forces
A force acting on the outside of a structure set in equilibrium
Internal Forces
a force effect within the entity or any component part of a structure set in equilibrium
Collinear Forces
force acting along the same line of action
Coplanar Forces
forces that all lie in the same plane
Concurrent Forces
forces that all intersect at a common point.
General Space Force System
Non-coplanar, non-parallel, non-concurrent, con-collinear force system
Moment
a moment of a force provides a measure of the tendency of a force to cause an object to rotate about a point or axis
Think Torque?
M = Fd (Scalar) M = r x F (Vector)
Parallelogram Rule
Head-to-tail addition of vectors
Moment
The tendency of a force to cause a rotation about a point or axis
Varignon’s Theorem
Can use the force or the component of a force to calculate the moment
Equivalence
All systems can be reduced to a single force and moment and in special situations can reduce to a single force at a known location
Transmissibility
Does not matter whether you push or pull as long as you maintain the same line of action. The result is the same
Lateral Transfer Theorem
Allows the moment of a force laterally (Different from the line of action)
As long a moment (couple) is added
Superposition
As long as there is linearity, a complex problem can be broken down into simpler pieces and summed
Friction
Columb’s Law of dry friction which is empirical in nature
not derived, but observed
Area Moment of Inertia
Stiffness parameter based on shape
