Mechanics vocab - simple pendulum
Term | Definition |
Velocity (v) | Vector quantity of speed and direction of an object |
Relative motion (velocity) | Comparison of two or more objects' motions, assuming that the second object is fixed by looking at the reference frame of the second object |
Trajectory | The path of an object in projectile motion |
Kinetic friction (force) | Opposes sliding motion, constant |
Static friction (force) | Prevents motion |
Normal force (N) | Support force exerted by a surface perpendicular to the surface itself |
Tension (T) | Pulling force transmitted through a sting, rope or cable when stretched, equal throughout |
Elastic force | Restoring force exerted by an object when it is deformed |
Buoyant force (N) | Upward force exerted by a fluid on a submerged object |
Archimedes' principle | The buoyant force exerted to an submerged object is equal to the weight of the submerged weight of the fluid it displaced |
Transactional equilibrium | Sum of all forces in any direction is zero |
Rotational equilibrium | Sum of all torques about any pivot point is zero |
Torque (τ) | Rotational effect of a force applied at a distance from a pivot point |
Couple of forces | A pair of equal and opposite forces acting on a body but not along the same like, causing torque but no rotation |
Center of mass | Point where the entire mass of an object or system can be considered to be concentrated for motion analysis |
Newton's I law | If an object is not interacting with other objects (affected by forces) it remains at rest or continues to move in a straight line with constant speed |
Newton's II law | The net force acting on an object gives it an acceleration proportional to the force (motion equation) |
Newton's III law | When two objecst interact, they exert forces on each other that are equal in magnitude but opposite in direction |
Rolling resistance | Force that opposes the motion of a rolling object due to deformation, internal friction and surface interaction |
Air resistance | Drag force that opposes the motion of an object moving through air |
Terminal velocity | Maximum speed attainable by an object falling through a fluid / gas. Sum of drag force and buoyancy is equal to the downward force of gravity |
! Coefficent of restitution ( e ) | Measurement of how "bouncy" a collision is between two objects. Reread notes on what kind of collisions have what kind of coefficents of restitutions |
Principle of work and kinetic energy | Work done by the sum of all forces acting on a particle is equal to the change in the kinetic energy of the particle |
Impulse (J) | Change in momentum caused by a force acting over a specific time interval |
Impulse-momentum theorem | Impulse is equal to the change in momentum |
Fission | Process where a single object splits into two or more parts. Total momentum of the system remains conserved. Ie a firework exploding |
Coalescence | Two or more objects combining to frm a single object. Total momentum of the system remains conserved. Ie two lumps of clay meet and stick together |
Elastic collision | Both momentum and kinetic energy are conserved. Coefficent of restitution is 1. Ie ideal gas molecule collisions, billiard balls |
Inelastic collision | Momentum is conserved, but kinetic energy is not, since some of it transforms into heat, sound etc. 0 < e < 1 |
Perfectly inelastic collision | Objects stick together after the collision. Momentum is conserved and e = 0 |
Uniform circular motion | An object moves in a circular path at constant speed |
Linear velocity (v) | Speed of an object on its circular path |
Angular velocity () | Circular motion speed in rad / s |
Period (T) | Time to complete one full revolution (2π) |
Rotational frequency (f) | Number of revolutions per second, measured in Hz |
Centripetal force | Force that causes circular motion. Directed towards the middle of circular motion. |
Non-uniform circular motion | In non-uniform circular motion the object is speeding up or slowing down during circular motion. In addition to addition to centripetal acceleration, there's also tangential acceleration, which causes the change in speed |
Inertial force | Force that appears when looking a acclerating force at a rotating reference frame. |
Centrifugal force | Type of inertial force that appears in a rotating (non-inertial) reference frame, acting away from the center of rotation. Equal to ventripetal force, but points in the opposite direction. |
Inertia | Resistance to a change in motion |
Simple harmonic motion | Periodic motion, which is similiar to uniform circular motion in nature. Most commonly a weightless, lossless spring in a vacuum. |
Restoring Force | The force that pulls the object back toward equilibrium. |
Amplitude (A) | The maximum displacement from equilibrium in harmonic motion |
Period (T) | The time for one full oscillation (one wavelength/rotation) |
Frequency (f) | How many oscillations occur per second. |
Phase (ϕ) | Determines the starting position of the motion. |
Angular Frequency (ω) | A measure of how fast the system oscillates in radians per second. |
Simple pendulum | A mass attached to a rod pivited in it's other end. |