 What does a ball drop from height, a ball rolling down an inclined plane and a box which is being pushed to the right moving with an increasing velocity on a rough surface, what do these three have in common? Turns out each one of these they represent a motion with constant acceleration. For the first case, there is a constant acceleration which is acceleration due to gravity. There is a G which acts on the ball at all the points and as a result of which the speed with which the ball falls it increases. So at the beginning there is no speed but it increases somewhat over here then it increases some more then it increases even more as it keeps on falling. For this fun when the ball is rolling down an inclined plane, there is still gravity acting on the ball and we will learn how to resolve this vector of gravity into a horizontal and a vertical component and then we will see how there is still one constant acceleration which is acting on the ball and because of which it is then coming down it is then moving moving with an increasing velocity and for this case if the block is moving to the right with an increasing velocity and this is a rough surface we will see that there is there will be a frictional force that will act on the block on the left side there will be a frictional force that will act on the left side and then this person is pushing the box to the right with a force of F and we will see that if a block moves to the right with an increasing velocity which means there is an acceleration to the right there is an there is an acceleration to the right and we will see that whenever there is some net force acting on an object so whenever F is greater than the frictional force the block will move to the right with an increasing velocity or a constant acceleration in all of these three cases the acceleration is constant and turns out that's why we study motion with constant acceleration not just motion with constant velocity because in the case of free fall or a ball rolling down the inclined plane or a very usual situation of someone pushing the box on a rough surface and the speed of the box constantly increasing in all of these cases the only thing that is constant is the acceleration with which these objects are moving and motion with constant acceleration is even seen if there's a car moving moving on this road and it suddenly applies a break because of because it does not want to collide with some other car or does not want to get into an accident when it suddenly applies breaks it comes to a stop and then it leaves it leaves these skid marks it leaves these skid marks but unfortunately still if the car does get into a crash investigators can actually tell how fast the car was moving to begin with and this is again a case of motion with constant acceleration because when you apply the brake the frictional force between the road and the tire it's it acts in the opposite direction which provides a constant acceleration in the opposite direction so this is again a case of motion with constant acceleration and turns out there will be many more cases where the acceleration is constant where the velocity could be increasing or decreasing if depending on whether the acceleration is in the same direction of the velocity vector or in the opposite direction and we will try and analyze such cases we will come with kinematic equations that will help us predict many variables associated with the motion of an object