Highlights Flashcards
What is Law of Inertia?
-Is also called Newton’s First Law of Motion.
-States that an object at rest or at the state of motion remains in its state until external force is applied
What is Law of Action and Reaction?
-Is the Newton’s Third Law of Motion.
-States that “Every action has its equal and opposite reaction”
What is the formula for Force acting on a body?
F=ma
Where
-m: is mass of object
-a: is acceleration of object
What is formula for Momentum of a body?
F=mv
Where
-m: mass of object
-v: is velocity of object
What is Hooke’s Law?
-Hooke’s Law states that, the restoring force in a spring is derectly proportiomal to the displacement of the spring from its mean position.
-Is a principal of physics that state that the force (F) needs to extend or compress a spring by some distance (x). (x) is proportional to that distance
F=-kx
Where
-F: force
-x: extension
-k: constant force (or constant spring)
Why the value of k in Hooke’s Law is negative?
The negative sign indicates the direction of the force.
The convention is that the force excerted by the spring is opposite to the direction of displacement
What are limitations in Hooke’s Law?
-Hooke’s Law only applies to elastic materials.
-Hooke’s Law is not applicable after elastic limit of any material is reached.
-Beyond the limit, elastic materials can experience permanent deformation or even break
Why are bridges declared unsafe after long use?
Because bridges uses elastic materials and these lose strenght after repeated use
When does Hooke’s fail?
When an elastic material goes beyond its limit
Name types of strain:
-Longitudinal
-Volumetric
-Shear
Newton’s First Law
-An object on rest will remain at rest and an object on constant motion will remain on its states unless an external force is applied
-Is the Law of Inertia
-When forces are balanced, the acceleration is zero.
-Net force is zero
Newton’s Second Law
-Refers to the Behaviour of objects which unbalaced forces.
-States that the ecceleration of an object depend on two variables: net force acting upon the object and the mass of the object.
-The acceleration of an object is directly proportional to the magnitud of the net force and inversely proportional to the mass of the object.
-Force=mass x acceleration
F=ma
-Force and Momentum
Momentum=mass x velocity
Newton’s Third Law
-For every action there is an equal and opposite reaction
-Is also known as Law of action and reaction
-The magnitud of the first object is the same as the as the second object
-The direction of the of the forces are opposite
Young’s Modulus
Young’ Modulus= stress/strain
-Is also known as Modulus of Elasticity
-Provides the realtion between material and stress
-It defines the elastic characheristics of solid that is subject to tension or compression
-High Young’s Modulus in object: value is elastic
-Low Young’s Modulus in object: value is inelastic
Definine Young Modulus of a material and state when it applies
-Young Modulus=stress/strain
-As long as the elastic limit is not exceded
-In linear the linear region of stress against strain graph
-Hooke’s Law is obeyed
