Projectile Motion/classical mechanics

joey12345

Looking over some subjects I'll be doing next year and classical mechanics is one of them and this problem keeps coming up.

A projectile is launched with initial velocity v0 from a height h at an angle alpha to the horizontal. What is the greatest height reached. Speed upon impact etc the rest are the typical projectile motion questions.

Without having started the module I can find all the typical things asked but when it's launched from the horizontal directly not from a given height h. What changes in getting your answers?


And where should you go next if your just looking over things before you start the subject like I know the blocks on inclined Planes but what of circular motion and things like that any good websites or PDFs for downloads that anyone knows?

Kavrocks

I don't know how you do these questions but I get V (Velocity) and S (Displacement) equations 1 of each for both X and Y. In the case where you are a height h above the surface you just add h to your Sy equation so that when t=0 Sy will be 0 which is your height above the ground.

I'd recommend looking at the Applied Maths leaving cert course.

Neodymium

I think I'm in a similar situation to you. I will be going into a physics course this September and I didn't have applied maths done for the leaving cert so I decided to go over the applied maths course myself to make life a bit easier next year. Try and get your hands on a book called "fundamental applied mathematics" by Oliver Murphy.

For your question, just find the maximum height reached as you would normally and add the height h on to it. The maximum distance in the y-direction will occur at the same time as the velocity in the y-direction=0. Get your velocity in the y-direction in terms of time and substitute this value into your equation for the displacement in the y-direction and add the height h onto it, this should be the maximum height.

haribos

Not sure if in PDF or not but most colleges these days use R.C Hibbeler's Statics and Dynamics Books, obviously your looking at Dynamics.
The books are absolutely brilliant, see if you can find pdf or a cheap copy!

joey12345

thanks for the replies everyone i downloaded that book and you were right its very good and very easy to read thanks again