What is Kinematics in Physics

Definition of Kinematics

Kinematics, in physics, is the study of motion of particles or systems of particles, without taking into consideration the masses of the particles or the forces that cause them to move.

Study of quantities such as displacement, velocity, and acceleration fall under the purview of kinematics in physics.

What is Displacement

Displacement measures the difference between a particle’s initial and final position. If the position vector of the particle’s initial position, \vec{r_{i}},  is \vec{r_{i}} = \left (r_{ix}, r_{iy}, r_{iz}\right ) and the position vector of the particle’s final position, \vec{r_{f}}, is \vec{r_{f}} = \left (r_{fx}, r_{fy}, r_{fz}\right ), then the displacement \Delta\vec{r} of the particle is given by:

\Delta\vec{r} = \vec{r_{f}} - \vec{r_{i}} = \left (r_{fx} - r_{ix}, r_{fy} - r_{iy}, r_{fz} - r_{iz}\right ).

How to Calculate Displacement

What is Velocity

Velocity is the rate of change of position with respect to time. It is defined as:

\vec{v} = \lim_{\Delta t\rightarrow 0} \frac{\Delta x}{\Delta t} = \frac{\mathrm{d} \vec{r}}{\mathrm{d} t}.

What is Acceleration

Acceleration is the rate of change of velocity with respect to time. It is defined as:

\vec{a} = \lim_{\Delta t\rightarrow 0} \frac{\Delta v}{\Delta t} = \frac{\mathrm{d} \vec{v}}{\mathrm{d} t}.

What is One-dimensional Kinematics

One-dimensional kinematics is the kinematics of particles moving along a line, i.e., in one spatial dimension.

Under one-dimensional kinematics in physics, we consider a particle moving along a straight line. We can derive equations of motion for the special case where the acceleration is constant. In deriving these equations of motion, we will assume that the particle is moving only in a straight line along the x-axis.

If acceleration is uniform, then, over a given period of time \Delta t, the average velocity  v_{av} is given by \frac{1}{2} (v_{f} + v_{i}), where v_{i}  is the velocity of the particle at the beginning of the time period and v_{f} is the velocity of the particle at the end of the time period. In this case, the total displacement, \Delta x, is simply the product of the average velocity and time:

Deriving 'suvat' equations

Deriving 'suvat' equations

What is Two-dimensional Kinematics

Two-dimensional kinematics is concerned with particles moving in a plane, i.e., in two spatial dimensions.

With two-dimensional kinematics in physics, in order to analyse two-dimensional motion, we resolve all vector components into two directions which are perpendicular to each other (for instance, the x– and y-axes on the Cartesian plane, or “vertical” and “horizontal” directions). Motion along one of these directions is then independent of the motion along the other. Consequently, equations of motion can be applied to each of these directions separately.

For example, consider a cannonball shot off from the ground at an angle \theta to the horizontal. In the  y-direction, the cannonball experiences a constant acceleration of  a_{y} = g= -9.81 m s-2. Horizontally, the acceleration is 0, assuming air resistance is negligible.

2 Dimentional Kinematics (Projectiles)

How to Solve Projectile Motion Problems

References

Kirkby, L. A. (2011). Physics A Student Companion. Scion Publishing.

Whittaker, E. T. (1904). A Treatise on the Analytical Dynamics of Particles & Rigid Bodies. Cambridge University Press.

About the Author: Nipun


Related pages


difference between zygote and fetusdifference between anorexic and bulimicsydney airport tax refundwhat is the difference between active voice and passive voiceexample of auditory imagerydifference between zygote and zygosporedifference between bajra and jowarbulldog differencesscientific definition of melting pointwhat is transitive and intransitive verbs with examplescharacteristics of a command economyunits for permittivity of free spacemalapropism examples in literaturewhat is the difference between atrial fibrillation and tachycardiainternal respiration occursverisimilitude in literaturedifference between bishop and pastorwhat is the difference between repetition and parallelismwhat is the difference between alpaca and a llamawhat is the structural difference between starch and celluloseexample of macronutrientsbelgian shepherd vs german shepherdvitamin b complex vs b12definition of cathode in chemistrydifference in ssri and snrimass moment of inertia unitsundamped oscillatorwhat is the difference between fettuccine and linguinedifference between diabetes and hypoglycemiadifference between uniform and nonuniform circular motionwhat is a agranulocytenon template strandprozac chemical formulaequilibrium quantity and price calculatorcommon adageprobiotics vs enzymesdifference between nationality and ethnicitychemical formula maltoseassimilation accommodation examplestransitive and intransitive verbs rulesare insects warm or cold bloodeddistillation and fractional distillationhoratian satire definitionwhat is diabetes mellitus and diabetes insipidussashimi translationmonoecious flowerwhat is ribose in biologyexplain the difference between pinocytosis and phagocytosisvoltmeter and ammeter differencecotyledon function in seedwhat are the differences between a stock and a brothfate and destiny differenceconceits examplesethnicity vs race vs nationalitymonocot and dicot differencebicameral legislature meaningrelationship between torque and horsepowerplant macronutrients and micronutrientsneutrophil basophil eosinophilexamples of polysemeswhat is symbolic imageryphonetics and phonology differencewhat is nucleoidelk vs reindeerdifference between anaerobic respiration and aerobic respirationaldehyde and ketonepolar or nonpolar moleculesdefine copolymerdifference between hotel and motel in hindileast count of vernier and micrometerwhat is the difference between inferring and predicting