ENGMECH Finals Flashcards
Physical science which deals with the effects of forces on objects. Oldest of the physical sciences.
Mechanics
Name the three parts of Mechanics and define them.
- Statics - deals with rigid bodies which are stationary or at constant velocity under action of forces. (Equilibrium of rigid bodies)
- Dynamics - deals with rigid bodies that are in motion.
- Mechanics of Deformable Bodies - deals with the internal effects of applied forces on non-rigid bodies.
What are the basic concepts of engineering mechanics?
- Space
- Time
- Mass
- Force
What is the difference between a rigid body and a non-rigid body?
A rigid body does not deform under the action of large forces meaning change in distance between any two points is negligible for the purpose at hand. A non-rigid body deforms under the action of large forces meaning any change would be considered.
Types of bodies investigated in engineering mechanics
Particles, rigid bodies, and non-rigid bodies.
A particle remains at rest or continues to move in a straight line with uniform velocity if there is no unbalanced force acting on it.
Newton’s First Law of Motion (Principle of Equilibrium)
The acceleration of a particle is proportional to the vector sum of forces acting on it, and is in the direction of this vector sum.
Newton’s Second Law of Motion (F=ma)
The forces of action and reaction between interacting bodies are equal in magnitude, opposite in direction, and collinear.
Newton’s Third Law of Motion (Law of Inertia)
What law is a consequence of Newton’s second law of motion such that no acceleration is present when the force is equal to 0 and the particle is either at rest or is moving with a uniform velocity?
Newton’s First Law of Motion (Principle of Equilibrium)
1 slug = _____ kg
14.59
1 kip = _____ lbs
1000
What is the gravitational acceleration in U.S. units?
32.2 ft/s^2
Differentiate scalar and vector quantities
Scalar quantities has magnitude while vector quantities has magnitude with direction.
An action of one body on another. It is a vector quantity.
Force
What is the difference between the external effect of forces and the internal effects of forces?
The external effect of forces is manifested in, or tendency to change, the state of motion of a body upon which the force acts. In other words, if there is no change in motion, the forces are said to be in equilibrium. The internal effect of forces produces stresses and strains within the body acted upon. These occurrences depend on the material properties of the body and is studied in regards to strength of materials, elasticity, and plasticity.
A force may be applied at any point on its given line of action without altering the resultant effects of the force external to the rigid body to which it acts. Thus, whenever we are interested in only the resultant external effects of a force, the force may be treated as a sliding vector.
Principle of transmissibility
Define contact force and a body force and give examples.
Contact force is produced by direct physical contact. Example is tension and compression forces as well as friction. Body force is generated by a body within a force field. Some examples include gravitational force and magnetic fields.
A set of 2 or more coplanar (2D) or spatial forces (3D) that may or may not be in equilibrium
Force Systems
Force systems can be _____ , _____ , or _____ .
Concurrent, parallel, or non-concurrent and non-parallel
A force system wherein two or more forces whose line of action intersect at a common point.
Concurrent force system
A force system wherein two or more forces whose line of action will never intersect.
Parallel force system
A force system wherein two or more forces are neither concurrent nor parallel.
Non-concurrent non-parallel force system