EJSS Projectile Motion Model for Primary School

EJSS Projectile Motion Model for Primary School

http://weelookang.blogspot.sg/2014/05/ejss-projectile-motion-model-for.html

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author: lookang
author EJS: Francisco Esquembre

Model

Projectile motion is a form of motion in which an object or particle (called a projectile) is thrown near the earth's surface, and it moves along a curved path under the action of gravity only. The only force of significance that acts on the object is gravity, which acts downward to cause a downward acceleration. There are no horizontal forces needed to maintain the horizontal motion – consistent with the concept of inertia.

The equation that model the motion of the ball is:

$ \frac{\delta x}{\delta t} = v_{x}$

$ \frac{\delta v_{y}}{\delta t} = a_{x} = 0$

$ \frac{\delta y}{\delta t} = v_{y}$

$ \frac{\delta v_{y}}{\delta t} = a_{y} = -9.81 $

Energy Equations:

$ Potential Energy = mgy $

where 

$ m $ is the mass of the object = 1 kg,

$ g $ is the gravitational acceleration in y direction = $ -9.81 \frac{m}{s^{2}} $

$ y $ is the position in the upward direction

$ Kinetic Energy = \frac{1}{2} mv^{2} $

where 

$ m $ is the mass of the object = 1 kg,

$ v $ is the velocity of the object