Mechanics Flashcards
What is a scalar
Physical quantity with a magnitude, but no direction.
Eg: time, mass, length, area, volume, energy, charge, pressure, charge
What’s a vector
Physical quantity that has both magnitude and direction.
Eg: force, velocity and electric field
Define resultant
A single vector that indicates magnitude and direction of the combine effect of two or more vectors
Bearing
Direction given as angle relative to north in clockwise direction
Define force
Any kind of push or pull on an object in an attempt to change object’s state of rest or motion
Contact force
Force exerted by objects on each other when they touch or connect with one another
Applied force
Force externally applied to an object
Normal force
contact force exerted by a surface on an object perpendicular to that surface
Tension
Force exerted by an object that can stretch
Friction
contact force that a surface exerts on an object parallel to the surface and opposite to the direction of motion or attempted motion
Static frictional force
Friction force exerted on an object that is not being set in motion.
Kinetic frictional force
Friction force that an object experiences when it moves over a surface
Non-contact force
Forces that objects exert on each other over a distance without touching each other
Magnetic force
attractive or repulsive force between magnetic objects
Electrostatic force
attractive or repulsive force between charges (charged objects)
State Newton’s first law of motion
An object continues in a state of rest or uniform velocity unless it is acted upon by an external net force
What is inertia
Property of a body that enables it to resist change in its motion
State Newton’s second law of motion
When a net force is applied to an object of a certain mass it accelerates in the direction of the net force. The objects acceleration is directly proportional to the net force applied to the object and inversely proportional to the object’s mass
What is uniform motion
Motion at a constant speed in a straight line
Net force or resultant force
Vector sum of all the forces acting on an object
Superposition
Addition of two or more effects at a single point in space
State Newton’s third law of motion
When object A exerts a force on object B, object B simultaneously exerts an opposite directed force of equal magnitude on object A
State Newton’s law of universal gravitation
Every particle in the universe exerts a force of attraction on every other particle. The force exerted by one particle on another is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
