MOTION IN A STRAIGHT LINE

MOTION IN A STRAIGHT LINE : -

INSTANTANEOUS VELOCITY AND SPEED :
The velocity at an instant is defined as the limit of the average velocity as the time
interval Δt becomes infinitesimally small. In other words, lim Where, the symbol  stands for the operation of taking limit as Δt® 0 of the quantity on its right. In the language of calculus, the quantity on the right hand side of equation is the differential coefficient of x with respect to t and is denoted .

ACCELERATION

The average acceleration a over a time interval is defined as the change of velocity divided by the time interval .where v2 and v1 are the instantaneous velocities or simply velocities at time t2 and t1. It is the average change of velocity per unit time. The SI unit of acceleration is ms–2. Since velocity is a quantity having both magnitude and direction, a change in velocity may involve either or both of these factors. Acceleration, therefore, may result from a change in speed (magnitude), a change in direction or changes in both. Like velocity, acceleration can also be positive, negative or zero.