UNIFORM MOTION IN A STRAIGHT LINE

An object is said to be in uniform motion if it undergoes equal discplacement in equal interval of time, howsoever small these intervals may be.

Consider an object in uniform motion along a straight line OX with a velocity &vcirc;. Let point O be the origin for position measurment. Let the time be measured from the instant the object is at O. Let A and B the postions of the object at the instants of time t1 and t2 respectively, where &OAcirc;=&x1circ; and &OBcirc;=&x2circ;

∴ Displacement of the object in time interval (t2-t1)=&ABcirc;=&OBcirc;-&OAcirc;=&x2circ;-&x1circ;

As, velocity= displacement/time interval

Important features of uniform motion

1. For a uniform motion along a straight line in a given direction , the magnitude of the displacement equal to the actual distance covered by the object.

2. The velocity in uniform motion does not depend upon the time interval.

3. The velocity in uniform motion is independent of choice of origin.

4. The Velocity of an object is taken to be positive if the object is moving towards the right of origin and is taken to be negetive if the object is moving towards the left of origin.

5. No force is required for an object to be in uniform motion.

6. The average and instantaneous velocities have same value in a uniform motion.

VELOCITY OF AN OBJECT

Velocity of an object is defined as the time rate of change of displacement of the object. It is defined as the speed of an object in a given direction.

Velocity is a vector quantity, as it has both, the magnitude(speed) and direction. The velocity of the object can be positive, zero and negative. according as its displacement is positive, zero or negative.

The unit of velocity is cm/s in cgs and m/s in mks systen or SI. The dimensional formula of velocity is

Types Of Velocity

(a) Uniform Velocity. An object is said to be moving with a uniform velocity if it undergoes equal displacement in equal interval of time, howsoever small these intervals may be.

(b) Variable velocity An object is said to be moving with a Variable velocity if it undergoes equal displacement in unequal interval of time or unequal displacement in equal intervals of time or changes direction of motion while moving with a constant speed.