Jousivoima

Jousivoima is a Finnish term that can refer to two related concepts in physics and archery. In physics, jousivoima denotes the restoring force that a spring exerts when it is stretched or compressed. According to Hooke’s law, the force is F = -k x, where F is the force, k is the spring constant, and x is the displacement from the equilibrium position. The force acts to restore the spring to its resting length, and its magnitude increases linearly with displacement for an ideal spring. The corresponding potential energy stored in the spring is U = 1/2 k x^2. Jousivoima is measured in newtons, with k in newtons per meter and x in meters. Real springs can deviate from linearity, especially outside the elastic range.

In archery, jousivoima refers to the draw weight—the force the archer must apply to draw the bow to a specified draw length. Draw weight is typically given for a standard draw length, often around 28 inches in many standards, and varies with bow design (recurve, longbow, compound) and with limb stiffness and configuration. A higher draw weight means more energy is stored when the bow is drawn, which can yield higher arrow speeds but requires greater effort from the archer. The energy stored in the bow is approximately the area under the draw-force curve as the string is drawn, and this energy influences the arrow’s velocity and flight characteristics.

Overall, jousivoima connects fundamental mechanics with practical applications in sport and engineering, illustrating how a simple restoring force governs both elastic systems and archery equipment.