Average Velocity And AverageSpeed | Motion In A Straight Line | Notes | Summary - Zigya

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Motion in Straight Line

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Average Velocity And AverageSpeed

Speed is defined as the distance travelled by a body per unit time. 
Thus,
Speed = Distance travelledTime taken           v = st

The SI unit of speed is ms-1 whenever the distance covered by the body is expressed in metre and time in second.
A smaller unit of speed is cm s-1.
A larger unit of speed is km h-1
Speed is a scalar quantity because it has only magnitude and no direction. 

The speed of a body tells us how fast or how slow the body is moving. But it does not give the direction of motion.

Dimension formula : [M0L1T-1]

Speed can be two types uniform speed and non-uniform speed.

In uniform speed, a particle covers equal distances in equal intervals of time.

In non-uniform speed particle covers unequal distances in equal intervals of time.

Average speed:

Average speed is defined as the total path length travelled divided by the total time interval during which the motion has taken place.

Average speed = Total path lengthTotal time interval

Average Velocity:

Average velocity is defined as the change in position or displacement (∆x) divided by the time intervals (∆t).

v = x2 -x1t2- t1 = xt

where x2 and x1 are the positions of the object at time t2and t1, respectively.

The bar over the symbol for velocity is a standard notation used to indicate an average quantity. The SI unit for velocity is m/s or ms–1.

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