Catapults Case

Catapults

Catapults are a lever-system built to launch objects long or short distances. There are several different kinds of catapults: weight-based, elastic-based, trebuchets, etc. Even though these catapults use different materials, they all do the same thing: Turn potential energy into kinetic energy, and using Newton's Laws. (Newton's 1st Law of Inertia, Newton's 2nd Law the relationship between two masses, Newton's 3rd Law for every action there is an equal and opposite reaction.)The elastic-based catapults can be built with either rubber cords, or springs. So when you press the lever against the rubber cords or springs, the force would create elastic potential energy which uses half Spring constant X (Distance compressed and stretched) the spring or cord without any force on its relaxed length (Newton's 2nd law will occur) When released from compression, the elastic potential energy will turn into kinetic energy launching the lever. The weight-based catapult uses gravitational potential energy to launch the lever. Dropping a heavy object onto one side, or releasing a heavy object on the launching side, will then cause gravitational potential energy energy due to: Mass X Freefall X Height. All of that energy will then change to kinetic energy making the catapult launch very far distances (Newton's 2nd law will ten occur). The levers of the catapult uses angular momentum, (Moment of inertia X angular speed) since all objects moving have inertia. This example shows that when a catapult decreases its movement of inertia, the angular speed increases, creating more kinetic force.

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