Question

The energy possessed by a stretched bow is:

• A. kinetic energy
• B. potential energy due to position
• C. potential energy due to strain
• D. mechanical energy

Answer 1

Answer:

C. potential energy due to strain

Understanding Energy in a Stretched Bow

• A stretched bow stores energy due to its deformation, specifically known as potential energy due to strain or elastic potential energy.

• Potential Energy Explained

  • Potential energy is the energy possessed by an object due to its position or state. It is stored energy that has the potential to do work.
  • Common forms include gravitational potential energy (due to height) and elastic potential energy (due to deformation).

• Elastic Potential Energy (Strain Energy)

  • When a material is stretched, compressed, or twisted (deformed), internal forces within the material resist this deformation. Work is done against these forces to change the object's shape.
  • This work done is stored as elastic potential energy within the deformed object.
  • For a stretched bow, the energy is stored in the bent limbs of the bowstring and the stretched string itself.
  • According to Hooke's Law, for elastic materials, the restoring force is directly proportional to the displacement (deformation), within the elastic limit. This law is fundamental to understanding elastic potential energy.

• Energy Transformation in a Bow and Arrow

  • When a bow is stretched, the muscular effort of the archer is converted into elastic potential energy stored in the bow.
  • Upon release, this stored elastic potential energy is converted into kinetic energy of the arrow, propelling it forward. This is a classic example of energy transformation.

• Key Facts for Competitive Exams

  • The unit of energy is the Joule (J) in the SI system. Other units include erg, calorie, and kilowatt-hour.
  • Energy is a scalar quantity, meaning it only has magnitude and no direction.
  • The Law of Conservation of Energy states that energy cannot be created or destroyed, but it can be transformed from one form to another. This principle applies to the bow and arrow system.
  • Examples of objects possessing elastic potential energy include a compressed spring, a stretched rubber band, and a winding clock spring.