The correct option is (a).
Explanation
Energy is the capacity to do work. Mechanical energy is broadly classified into two types:
- Kinetic Energy (K.E.): The energy possessed by an object by virtue of its motion. Mathematically, $K.E. = \frac{1}{2}mv^2$.
- Potential Energy (P.E.): The energy stored in an object by virtue of its position or configuration (shape/size).
Statement-wise Analysis:
- 1. A falling coconut: Since the coconut is falling, it is in motion. Therefore, it possesses Kinetic Energy. (It also loses Potential Energy as it falls, converting it into Kinetic Energy).
- 2. A speeding car: A car moving with speed possesses motion. Therefore, it has Kinetic Energy.
- 3. Blowing wind: Wind is essentially air in motion. Moving air molecules possess Kinetic Energy, which is utilized in technologies like windmills.
- 4. A compressed spring: A compressed spring is stationary but has undergone a change in configuration (deformation). The energy stored in it is Elastic Potential Energy, not Kinetic Energy.
Key Takeaway:
Any object in motion possesses Kinetic Energy. Objects that are stationary but have stored energy due to height (gravitational) or deformation (elastic) possess Potential Energy.