I want to know why does Mr.Lewin say that the initial velocity in y direction is zero but not along x?? I am sorry for the confusin.... I meant in the MIT lec3 of classical mechanics... Mr.Lewin says that the initial velocity along y is zero but not along x, I want to know why?

Question

stormfire1 · Answer

You need to clarify your question.  Which video?  At what time in the video is he talking about this?

anonymous · Answer

yeah, you have to specify a little bit

anonymous · Answer

Yes you meat clarify the question for me to help you

anonymous · Answer

I am going to assume you are talking about a horizontal projectile problem. Ex: a ball rolling off the edge of a table. The ball is not experiencing any displacement in the vertical direction until just after it becomes a projectile. So, it's initial vertical velocity is zero, while its initial horizontal velocity is the same as when it was rolling on the table.

anonymous · Answer

why  the initial velocity along y is zero but not along x ? : actually I didn't understand your question , but you can read about : projectiles launched at an angle .

anonymous · Answer

ibelieve you are speakin of projectile motion....initially its vcostheta along x axis and vsintheta along y-axis...when a ball is released horizontally from a platform its vertical velocity is zero but not the horizontal.........