Why does a catapult work

The catapult arm is pushing up on my hand with a lot of force, but my hand is pushing back, in the opposite direction, making the catapult arm move downwards.

Does the length of a catapult arm affect distance? Overall, as the arm length of the catapult increased, the ball was thrown farther.

My hypothesis was that a ball being thrown from a catapult, will travel a farther distance if it is thrown using a longer arm. This shows that extending the arm length does increase the distance thrown. How do you make a strong catapult? To build a strong catapult, build a base supported with plywood triangles, with a cross brace at the top. Attach a launching basket to the throwing arm, and attach the arm to the base at one end with a long piece of rope that is wrapped through the frame and around the arm in an over-under-over pattern.

What are catapults made of? Nearly all catapults employed in ancient and medieval artillery operated by a sudden release of tension on bent wooden beams or of torsion in twisted cords of horsehair, gut, sinew, or other fibres.

An exception was the medieval trebuchet, powered by gravity. How far can a catapult shoot? How strong is a ballista? The ballista was a highly accurate weapon there are many accounts of single soldiers being picked off by ballista operators , but some design aspects meant it could compromise its accuracy for range. The maximum range was over yards m , but effective combat range for many targets was far shorter. What type of a simple machine is a catapult?

Who invented catapults? This is the heart of the physics behind a trebuchet and is the reason why a trebuchet has such great launching power. For a more in-depth explanation on how a trebuchet works see Trebuchet Physics. In this page the basic equations describing the physics of a trebuchet will be introduced. To assist you in building a trebuchet you can use this simulator to help you come up with the design that throws the payload the farthest.

This is very useful for helping you come up with the winning design in a trebuchet competition! In the next section we will look at the mangonel. Author: ChrisO The above picture of the mangonel is what people are most familiar with when they think of catapults. The mangonel consists of an arm with a bowl-shaped bucket attached to the end.

In this bucket a payload is placed. Upon release, the arm rotates at a high speed and throws the payload out of the bucket, towards the target. The launch velocity of the payload is equal to the velocity of the arm at the bucket end. The launch angle of the payload is controlled by stopping the arm using a crossbar.

This crossbar is positioned so as to stop the arm at the desired angle which results in the payload being launched out of the bucket at the desired launch angle. This crossbar can be padded to cushion the impact. The mangonel was best suited for launching projectiles at lower angles to the horizontal, which was useful for destroying walls, as opposed to the trebuchet which was well suited for launching projectiles over walls. However, the mangonel is not as energy efficient as the trebuchet for the main reason that the arm reaches a high speed during the launch.

This means that a large percentage of the stored energy goes into accelerating the arm, which is energy wasted. This is unavoidable however, since the payload can only be launched at high speed if the arm is rotating at high speed. So the only way to waste as little energy as possible is to make the arm and bucket as light as possible, while still being strong enough to resist the forces experienced during launch.

The physics behind a mangonel is basically the use of an energy storage mechanism to rotate the arm. Unlike a trebuchet, this mechanism is more direct. It consists of either a tension device or a torsion device which is directly connected to the arm. The figure below illustrates a mangonel in which the energy source is a bent cantilever, which is a form of tension device. This can consist of a flexible bow-shaped material, made of wood for example.

Secure these sticks together by wrapping rubber bands around both ends of the stack. You will anchor the launching stick to this stack, as described in the next step. To add the launching stick take one stick and attach it perpendicular to the stack you just made, around the middle, so you get a cross shape. You can do this with one or two rubber bands that are crossed in an X over the sticks. If you cross it this way, the sticks will stay nicely perpendicular. Next, add the base by attaching a stick to one end of the launching stick with a rubber band.

If it were not for the stack of sticks in between, the launching stick would fall flat on top of the base. Now the launching stick and the base form a V shape lying on its side with the stack of sticks in the middle.

Put your catapult on its base, locate the end of the launching stick that sticks up and glue the bottle cap there so it forms a small cup to hold the missile. Wait until the glue is dry. Procedure Put your catapult in an open area with a sturdy, flat surface such as a table or an open space on a hard floor. Clear about a meter of open space for the launched object the missile to fly and land.

Place a cotton ball in the launching cup, push the cup down just a little bit and let go. What happened to the ball? Did it fly? Did it go high or low? Where did it land? What do you expect will happen when you push the cup farther down?

Will this make it fly higher, farther, both higher and farther or take the same path but maybe faster? Perform a test: Put your cotton ball in the cup, push the cup down farther, release and observe.

You might need to repeat the test a few times to make your observations. It all happens fast! Does your ball fly higher or lower? Does it land farther or nearer when you push down a lot compared with when you push down a little? Did you notice in which case you needed to do the most work?

Is it when you pushed down a little or when you pushed down farther? Try more launches. Do you get similar results each time? Is what you observe what you expected? Can you explain why?