# when we throw a ball frm the ground,we say it is following projectile motion and in projectile motion we consider 0 accleration in the horizontal direction.so in this case how can we neglect the accleration in the horizontal direction,because if i am throwing the ball then i am applying some force and that force is impartting acclerationin in the slanting direction.so this accleration will definitely have horizontal component.so how can we say that no accleration in the horizontal direction.plsssssssssssssssssssss analyse the seachuation and make me clear.

68 Points
13 years ago
`Dear   vijay kumar pandey, When you throw a ball you definitely apply certain force as per FIRST LAW OF motion which says  that it is essential to apply a force if you want a body to change its state of motion . so you apply the force .  but to solve the questions you need to  consider only that part in which body is in air and then body has already slipped from the hands so no force is applied by the thrower WHILE IN AIR . only gravitational force acts and we say to neglect other horizontal  forces such as air drag . hope this clears the doubt..Please feel free to post as many doubts on our discussion forum as you can. We are all IITians and here to help you in your IIT JEE preparation. Now you can win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.`
souvik das
33 Points
13 years ago

You are imparting a force at the time of projection which is accelerating the ball to a certain uniform velocity but there is no constant acc. provided by you through out the projectile motion which will provide a component of acc. in horizontal direction. The vertical negative acc. comes from gravity.