Question

A 5 metre long wire is fixed to the ceiling. A weight of 10kg is hung at the lower end and is 1metre above the floor. The wire was elongated by 1mm. The energy stored in the wire due to stretched is
(A) zero
(B) 0.05joule
(C) 100 joule
(D) 500 joule

Answer 1

Hint
Energy is defined as the ability to do work. Energy can be found in many things and can take different forms. For example, kinetic energy is the energy of motion, and potential energy is energy due to an object's position or structure. Energy is never lost, but it can be converted from one form to another.

Complete step by step answer
So, according to the formula
So the energy, $ W = \dfrac{1}{2} \times F \times l $
Now, we can say F = mg
 $ W = \dfrac{1}{2} \times 10 \times 10 \times 1 \times {10^{ - 3}} $
∴ W = 0.05 J.
Option (B) is correct.

Note
The most common definition of energy is the work that a certain force (gravitational, electromagnetic, etc) can do. Due to a variety of forces, energy has many different forms (gravitational, electric, heat, etc.) that can be grouped into two major categories: kinetic energy and potential energy.