The idea of the trebuchet design relies on the principle that stored potential energy of the counterweight can be converted into kinetic energy of the projectile, launching it into the air. Having the counterweight pivot around a much shorter distance than the projectile end gives an advantage to the projectile end of the beam to reach a much higher linear velocity than the counterweight end of the beam. This is the principle mechanical advantage that allows the projectile to have a high launch velocity. The main goal is to maximize the ratio of the length of the arm to the distance in which the apple travels.
While drag and gravity are the only forces acting on the apple after it’s been released, there are many forces that act on the trebuchet
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If we let the origin be at the pivot point, the torque created by this force can be modeled by torque(weight)= M*g*.21*cos(훳) Nm
Where 훳 equals the angle of the arm with respect to the horizontal. There is also a torque acting in the counterclockwise direction. This force is caused by the mass of the arm. It can be reasonably assumed that the arm has a uniform density since the thickness is the same throughout and the arm is made of only one material, and so we can say that the center of mass must be located at the midpoint of the arm. Using this, we can model the torque caused by the mass of the arm by torque(bar)= (mass of bar)*g*.79*cos(훳) Nm where 훳 is the same as 훳 in the previous equation. This means the total torque can be measured by summing those two values. The trebuchet creates it’s own system of transferred energy. Due to air resistance and the presence of friction, the energy is not conserved throughout the system. The system loses energy during the apples parabolic flight. The work done by the drag force (air resistance) makes the horizontal distance be less than expected. The energy of this system starts as a potential energy coming from the hanging mass that exists at the end of the lever arm. When the calculations are to be put into place, we can set the height to be at the base of the trebuchet. Using the equation for potential
For almost as long as civilizations began they have been fighting against each other. Often times these wars come down to who has the better military equipment. When one army creates an elite war machine another army is sure to soon copy or improve it. For example the U.S. Army Signal Corps purchased the first ever military aircraft in 1902 (Taylor). Two years later the Italians were also using aircrafts. The trebuchet catapult is no exception; it was one of the most destructive military machines of its time (Chevedden, 2000). A trebuchet works by using the energy of a falling counterweight to launch a projectile (Trebuchet). In this research paper I intend to explain the history and dynamics of a trebuchet catapult.
Before the days of gunpowder, the military used large timber machines to hurl rocks, arrows and flaming barrels of tar at and into castles and forts. In ancient times, in order to prevent attacks from invaders, forts and castles are built for protection. These castles and forts had very strong walls and were sometimes placed high on top of a hill or such. Therefore, people within the military often build machines and structures to aid in attacking castles. These machines were called catapults, which didn’t use explosives like today’s military weapons, instead they used energy which was stored in bent timber and sinew, twisted ropes or heavy weights. A catapult is a machine that initially stores energy and then releases energy in order to fire a projectile. In simple terms, it is a device that is used to hurl an object to a further distance. In order to be classified as a catapult, the machine generally has to be larger than an average person, which logically makes it difficult for the said person to carry. The first catapults were early
Torque= Force x radius , since the radius is half the diameter , T=F x D/2
Standing some 3 feet tall, this trebuchet could repeatedly launch a 2-3oz object in excess of 20 feet.
Non-trebuchet catapults are powered by torsion. The energy is stored in twisted animal sinew or vine-based ropes. Trebuchets are powered by a large counterweight or counterforce, which when released, falls and pulls a swing arm up and over with a sling containing the projectile. At the right angle the sling is released sending the projectile to the target. In its simplest form, a trebuchet is a lever.
I predict that the further I pull the band back the further it will ‘fly’. This is based on the fact that the more tension involved means that the potential energy is greater therefore the kinetic/moving energy will also be greater.
Before continuing much further, there are a few terms that need to be defined. First and foremost are the two main forces that act upon the boomerang, tension and compression. Tension is the force acting upon the side of the boomilever that is being “pulled” away from the wall, or the top side. On the other end of the spectrum is compression, which is the force acting on the side of the boomilever being pushed toward the wall, or the bottom of the device. Generally, compression is the main concern in building.
First the energy of conservation. The setting of the trebuchet before firing is shown in Fig 1. A heavy counterweight of mass (M) (contained in a large bucket) on the end of the short arm of a sturdy beam was raised to some height while a smaller mass (m) (the projectile), was positioned on the end of the longer arm near or on the ground. In practice the projectile was usually placed in a leather sling attached to the end of the longer arm. However for simplicity, we shall ignore the sling and compensate for this omission by increasing the assumed length of the beam on the projectile’s side. The counterweight was then allowed to fall so that the longer arm swung upward, the sling following, and the projectile was ultimately thrown from its container at some point near the top of the arc. The far end of the sling was attached to the arm by a rope in such a way that the release occurred at a launching angle near the optimum value ( most likely by repeated trials) for the launch height. The launching position is shown in fig.2 where we have assumed that the projectile is released at the moment the entire beam is vertical. In the figures: (a)=height of the pivot, (b)= length of the short arm, (c)= length of the long arm, while (v) and (V) are the velocities of (m) and (M), respectively, at the moment of launching.
This paper will explain a few of the key concepts behind the physics of skydiving. First we will explore why a skydiver accelerates after he leaps out of the plane before his jump, second we will try and explain the drag forces effecting the skydiver, and lastly we will attempt to explain how terminal velocity works.
This summer when you go to weigh that fat juicy watermelon, think about the mechanics of how the scale works. The basket is attached to a spring that stretches in response to the weight of the melon or other objects placed in it. The weight of the melon creates a downward force. This causes the spring to stretch and increase its upward force, which equalizes the difference between the two forces. As the spring is stretched, a dial calibrated to the spring registers a weight. When designing scales one needs to take into account that every spring has a different spring constant (k). Bloomfield (1997) defines k as “a measure of the spring’s stiffness. The larger the spring constant-that is, the stiffer the spring-the larger the restoring forces the spring exerts” (p. 82).
F = ma : where F is force; m is the mass of the body; and a is the acceleration due to that particular force
== == Flywheel String Slotted mass on hanger Stop-watch Vernier caliper Metre ruler Theory = ==
There are two forces, which affect the spring. The first force is gravity which is the force exerted by the gravitational field of a massive object on body within the vicinity of its surface. The force of gravity on earth has value approximately 9.81 m/s2 and always equals to the weight of the object as the equation: F = mg. m is mass (in kg) and g is gravity on earth (John, 2009). The second force is spring force; the magnitude of the force is directly proportional to the amount of stretch or compression of the spring.
Archery, a sport that dates back to centuries before today, has been modernized to become more efficient and high tech. The Egyptian made the first complex bow in 2800 BC. The bow was made from sheep intestines and the arrow was light and efficient enough to be shot from 400 yards away and still penetrate the armor used at that time. Archery was a skill set that was prized in the military, especially in Rome. However, in 16th century a new tide was turning in Europe, firearms were slowly replacing the bow and arrow as military weapons. Other parts of the world were not as fast to leave behind archery this weapon. The people of the Far East employed archery in warfare until the 19th century, while people in Central and South Africa still use it to this day for hunting and intertribal fighting. Archery, in many parts of the world today, is viewed by some as a recreational sport and by others, as a competitive sport. Due to this, the shapes of the bow and the arrow have gone through many changes since the first model of the bow and arrow.
Projectile motion is the force that acts upon an object that is released or thrown into the air. Once the object is in the air, the object has two significant forces acting upon it at the time of release. These forces are also known as horizontal and vertical forces. These forces determine the flight path and are affected by gravity, air resistance, angle of release, speed of release, height of release and spin