# projectiles

projectiles

Teacher recommended

- Created by: Nicola
- Created on: 24-06-10 01:39

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W6.1 Projectiles

This is where two dimensional motion is probably most easily done in

components

rather than in vectors.

We shall first consider an example taking place entirely on horizontal ground

projected from ground level and landing at ground level.

In all our examples, we shall ignore air resistance.

Ex

A ball is kicked at 15ms-1 at an angle of 25° above the horizontal.

How high does it go

and how far away does it land?

Its initial velocity can be split into two components:

15 cos 25° horizontally

and 15 sin 25° vertically upwards.

We shall first find how high it goes.

There are two ways.

Both of them depend on locating where or when the vertical component

of the velocity is zero.

First, to locate where that happens.

= + 2as 0= 2gs

s= = 2.05m

We could also find when that happens.

v = u + at 0 = 15 sin 25° gt

t= = 0.646s

We shall see later that the particle's trajectory is as symmetrical as we're

inclined to draw it.

CT Training 02/05/2010

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