Speed of an Object

Speed of an object is defined as the time rate of change of position of the object in any direction, It is measured by the distance travelled by the object in unit time in any direction

speed=(distance travlled)/(time taken)

speed is scalar quantity.It gives no idea about the direction of motion of the object. The speed of the object can be zero or positive but never negetive.

The unit of speed is cms-1 in cgs system and ms-1 in mks system or S.I. The dimensional formula of speed is[M0L1T-1]

Types of Speed

(a) Uniform Speed. An object is said to be moving with a uniform speed, if it covers equal distance in equal interval of time, howesover small these interval may be.

(b) Variable Speed. An object is said to be moving with a variable speed if it covers equal distance in unequal interval of time or unequal distances in equal interval of time, howsoever small these intervals may be

Average Speed When an object is moving with a variable speed, then the average speed oth the object is that constant speed with which the object covers the same distancein a given time as it does while moving with variable speed during the given time. Average speed for the given motion is defined as the ratio of total distance travelled by the object to the total time taken.