# projectiles (AS)

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i am really strugaling whith projectiles can someone help

Posted: 05-12-12 12:48 by daniel austin

Posted: 05-12-12 19:34 by Eamon Walker

based on the fact that I can't really guess on what topic of projectiles you are reffering to so...

http://physics.info/projectiles/

I found this website which might help :D

Posted: 05-12-12 19:37 by Eamon Walker

this is apparently AS so have a look and see what you understand:

http://www.s-cool.co.uk/a-level/physics/equations-of-motion/revise-it/projectile-motion-and-what-if-velocity-and-acceleratio

Posted: 05-12-12 19:50 by Eamon Walker

Some tips when doing projectiles:

+ Remember the horizontal and vertical motion are independent (do not use a vertical value when you are calculating horizontal values).

+ Remember the projectile decelerates until it reaches the top of it's trajectory (journey) and then it starts to accelerate downwards.

+ The projectile will follow a parabolic path.

+ The acceleration/deceleration will be the acceleration due to gravity.

+ The range is the horizontal distance and the maximum height is the vertical distance.

+ When you work out time using v = u + at or something like that, you have only worked out the time it takes the projectile to reach the top of it's trajectory - so multiply your answer by 2.

+ when calculating max height, you are looking at the first half of the journey only, so use half time.

+ when calculating range do not use acceleration because a projectile does not accelerate horizontally.

+ Remember that if a projectile is moving from say a table to the ground then it is like a half journey (half parabola) so you do not need to multiply time by 2.

+ Remember that air resistance can be ignored, so just put that to the back of your mind.

+ Remember the angle when working out horizontal and vertical components of initial velocity. IF the angle is to the horizontal then vcosx is the horizontal component (v = velocity, x = angle) and the vertical component is vsinx.

+ If you need to work out the initial velocity after having been given the horizontal and vertical components, use pythagoras.

+ If you need to work out the angle use trigonometry (SOHCAHTOA)

I hope this helps and has not confused you more : )

BTW do not do what I did in my mock and confuse horizontal and vertical components of motion - such a stupid mistake to make.

Posted: 05-12-12 20:12 by Former Member

Search for my newly made revision cards:

Projectiles: What to do and what not to do