Physics of Shooting a Bow and Arrow

John Willis

Driving Question

What really happens when a bowstring from a drawn bow is released?

The Bow

Bows come in many varieties – they could be made of wood, fiberglass, or spring steel.

Their main function is to store high amounts of potential energy and to release it into the nocked arrow as kinetic energy.

The Arrow

• Arrows are typically made of wood, aluminum, or carbon fibers.

• They are the ammunition for the bow.

• In pastimes, they had stone tips, but now they have aluminum tips that are changeable.

Physics

• The bow, when pulled back, stores massive amounts of potential energy. That potential energy is immediately converted into kinetic energy when the bowstring is released by the archer.

• When the kinetic energy forces the arrow forward, the arrow travels in the shape of a parabola. This is because the force of gravity is working against the force of the arrow, just like everything else it works against.

Physics

• Air works as a liquid to an arrow. This means that air creates drag for the arrow. Drag is a force that prevents something from moving; similar to friction.

Newton’s Laws of Motion

• Every object persists in its state of rest or uniform motion in a straight line unless it is compelled to change by forces impressed on it.

• Force is equal to change in momentum (mV) per change in time. For a constant mass, force equals mass times acceleration. F=ma

• For every action, there is an equal and opposite reaction

Citations

"Bow and Arrow - a History." Bow Hunting (bowhunting) & Bow Fishing (bowfishing) from ATHA Online Texas. Web. 10 May 2010.<http://www.athaonline.com/bow-and-arrow.html>.

"Arrow Flight." Physics Mr. Fizzix Mr. Physics High School Physics of Projects. Web. 10 May 2010. <http://www.mrfizzix.com/archery/aero.html>.

"The Bow." Physics Mr. Fizzix Mr. Physics High School Physics of Projects. Web. 10 May 2010. <http://www.mrfizzix.com/archery/bow.html>.

"The Bow." Physics Mr. Fizzix Mr. Physics High School Physics of Projects. Web. 10 May 2010.<http://mrfizzix.com/archery/types.html>.

"Newton's Laws of Motion." NASA - Title... Web. 13 May 2010.http://www.grc.nasa.gov/WWW/K-12/airplane/newton.html.