Projectile MotionFalling things, and rockets ‘n’ that…

Projectile Motion

This involves any objects under the influence of gravity.

• Objects which are dropped (not travelling horizontally) and

• Objects which are launched (with a horizontal component).

Objects Under the Influence of Gravity:

• Everything close to the Earth’s surface is accelerating towards the Earth at a rate of due to gravity.

• This means in problems involving falling we can always use a= in kinematic equations.

• For every kg of mass an object experiences a weight force of 9.81 Newtons (N)• Given by: W=mg

Where W is weight

Continued…

• What does this mean for objects dropped from the same height?• Objects dropped from the same height will hit the

ground at the same time, regardless of weight (ignoring differences in air resistance)

http://www.animations.physics.unsw.edu.au/jw/projectiles.htm#1

• Solve the same way you would any other kinematics problem… • State what you know, what do you want to find?• Choose an equation and solve for your unknown.• Look out for key words like.. “dropped”, “from rest” and “stationary:”

Rutter p.

32,33 – odd

questions

What will hit the ground first a bullet dropped or a bullet fired from the same height?

Discuss with your neighbour…

http://www.youtube.com/watch?v=D9wQVIEdKh8

Projectile Motion

• Projectile motion follows a parabolic path i.e. http://phet.colorado.edu/sims/projectile-motion/projectile-motion_en.html

• It has a horizontal (x) component and a vertical (y) component.

• The horizontal component is not affected by gravity, so use separate equations for the different components.

http://www.tutorvista.com/content/physics/physics-iii/kinematics/projectile-motion-animation.php