Uniformly Accelerated Motion
Objects on the earth surface are accelerated towards the centre of the earth at a rate of 9.8 m/ sec². If we raise an object above the surface of the earth and then drop it and the object will start from rest, its velocity will be increased by 9.8 m/ sec². For each second it is falling towards the earth surface until the object strike the ground.
What is Uniformly Accelerated Motion?
If the acceleration always remains constant, then that acceleration is called uniform acceleration. A movement with uniformly increasing or decreasing speed is called Uniformly Accelerated Motion. An object is said to moving with uniform acceleration, if equal change in velocity takes place in equal intervals of time, however small these intervals may be. In uniform acceleration, velocity changes with a uniform rate.
The acceleration of a freely falling object due to the gravitation is uniform acceleration. Equal forces act on an object of uniform acceleration, both magnitude and direction of uniform acceleration remains constant. So, it occurs when the speed of an object changes at a constant rate.
In the above figure uniform acceleration is shown by successive change of velocity with time along a straight line. The uniform acceleration of a body is 9 m/ sec means that the velocity of the body changes in each second by 9 m/ sec in the same direction.
How to find the Uniformly Accelerated Motion?
Problem: A car was travelling at a speed of 4.9 m/ sec, the driver saw a cat on the road and slammed on breaks. After 3 seconds the car came to stop, how far did the car travel from the point where the brakes were first passed to the point where the car stopped?
Solution: Given,
Initial Velocity (u) = 4.9 m/ sec
Final Velocity (V) = 0 m/ sec [∵ After some time car came to stop],
Time (t) = 6 sec
Distance (s) =?
Using Kinematic Relation:
\(Dis\tan ce\,\,(s)=\frac{(V+u)}{2}\times t\).
\(Dis\tan ce\,\,(s)=\frac{(4.9+0)}{2}\times 3=7.35m \).
Therefore, the car stopped after 7.35m.