Projectile Motion
When the player hits the “Sepak”, the motion of the “Sepak” is called projectile motion. The “Sepak” itself is called projectile. The “Sepak” will follow a parabolic path called trajectory especially if air resistance is negligible. Two coordinates are usually used to describe projectile motion: horizontal and vertical axes. The horizontal distance traveled by the projectile is called the range. While the vertical distance, that is, the distance from where it was launched to the top most point of its path is called its height.
Examples of projectiles are cannon ball launched by a cannon, golf ball hit by a golfer, and an ice skater jumping over some barrels. Usually, a strong, abrupt force initiates the motion of a projectile. Following this force, the projectile moves through the air and is influenced only by the earth’s gravitational force pulling it down and by air resistance. If the effect of air resistance is ignored, equations in free fall are readily used to analyze the motion of a projectile – how high it will travel, how far it will go and so on.
A remarkable thing to note is that the same range is obtained from two different projection angles – complementary angles. An object thrown into the air at an angle of 75o, for example, will have the same range as if it were thrown at the same speed at an angle of 15o. An object thrown at 60o will have the same range as when the object is launched at 30o. As you can see, when we get the sum of 75o angle and 15o angle, 60o angle and 30o angle, in both sets we would obtain a 90o angle. This means that 75o angle and 15o angle are called complementary angles. Similarly, 60o angle and 30o angle are also complementary angles. Thus, complementary angles (angles whose sum is equal to 90o) would result to equivalent range. For smaller angles, object remains in the air for a shorter time. A maximum range is attained when an object is launched 45o from the horizontal.