Which Energy System?

Year 11 Physics students have been learning about the various energy systems involved in firing a golf ball from a sling shot.

Assuming the catapult is built using some kind of lever and and an elastic band, then when an external force is applied to the lever to pull it back, it is transformed into kinetic energy. Most of that energy is transformed into elastic energy as it stretches the elastic band. This elastic energy is a form of potential energy.

Some of this energy is also transformed into heat energy and some of it may also be transformed into sound energy, if the catapult creaks. This heat and sound energy is lost from the system.

When the catapult is released, the potential energy is rapidly transformed into kinetic energy, moving the lever and its load. The lever transfers most of its kinetic energy into the projectile, which hopefully achieves a reasonable momentum. This will also lose some additional energy to heat and sound.

Kinetic energy is transformed into gravitational potential energy as it flies up, and then after it reaches its peak, that is then released again as kinetic energy downwards.

As the projectile flies through the air, some of its kinetic energy is transferred to the surrounding air as it pushes it out of the way. When it lands, that kinetic energy is transferred into the ground, which will then either use the kinetic energy for itself, or transform it into heat and sound.

The boys had fun in Mr Martinis class learning about all this


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