# NTNUJAVA Virtual Physics LaboratoryEnjoy the fun of physics with simulations! Backup site http://enjoy.phy.ntnu.edu.tw/ntnujava/

## Easy Java Simulations (2001- ) => kinematics => Topic started by: ahmedelshfie on June 09, 2010, 01:05:27 am

 Title: Trajectory of projectile motion Post by: ahmedelshfie on June 09, 2010, 01:05:27 am This following applet is Trajectory of projectile motionCreated by prof Hwang Modified by AhmedOriginal project Trajectory of projectile motion (http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1190.0)The initial speed of the projectile and the gravity can be changed with sliders.You can drag the far end of the bar to change the angle (it can be changed with the slider,too).You can find out at what angle the projectle will reach maximum horizontal distance when falls back to the same height.You can make your own demonstration:1. Replace the blue line with a stick.2. Prepare many strings with appropriate length (check out step 4),3. Loosely tie those strings at equal distance to the stick. (it will be better if you make a circle at one end of the string and put those strings at equal distance)4. Cut the strings so that the length L(i)=L*i*i;The distance between string represents initial speed of the projectile (distance travel at unit time).  Title: Re: Trajectory of projectile motion Post by: ahmedelshfie on June 26, 2010, 12:11:07 am A trajectory is the path a moving object follows through space as a function of time.The object might be a projectile or a satellite, for example. It thus includes the meaning of orbitâ€”the path of a planet, an asteroid or a comet as it travels around a central mass. A trajectory can be described mathematically either by the geometry of the path, or as the position of the object over time. Title: Re: Trajectory of projectile motion Post by: ahmedelshfie on June 26, 2010, 12:12:09 am A familiar example of a trajectory is the path of a projectile such as a thrown ball or rock. In a greatly simplified model the object moves only under the influence of a uniform homogenous gravitational force field. This can be a good approximation for a rock that is thrown for short distances for example, at the surface of the moon. In this simple approximation the trajectory takes the shape of a parabola. Generally, when determining trajectories it may be necessary to account for nonuniform gravitational forces, air resistance (drag and aerodynamics). This is the focus of the discipline of ballistics.One of the remarkable achievements of Newtonian mechanics was the derivation of the laws of Kepler, in the case of the gravitational field of a single point mass (representing the Sun). The trajectory is a conic section, like an ellipse or a parabola. This agrees with the observed orbits of planets and comets, to a reasonably good approximation. Although if a comet passes close to the Sun, then it is also influenced by other forces, such as the solar wind and radiation pressure, which modify the orbit, and cause the comet to eject material into space.Newton's theory later developed into the branch of theoretical physics known as classical mechanics. It employs the mathematics of differential calculus (which was, in fact, also initiated by Newton, in his youth). Over the centuries, countless scientists contributed to the development of these two disciplines. Classical mechanics became a most prominent demonstration of the power of rational thought, i.e. reason, in science as well as technology. It helps to understand and predict an enormous range of phenomena.