TECHNICAL FIELD: it The subject matter described herein, in general, relates to a shock absorber for a vehicle and in particular, relates to a shock absorber with a helper spring. BACKGROUND: A suspension system of a vehicle is located between wheel axles and the frame of the vehicle. The suspension system supports the weight of the vehicle and cushions the bumps on the road so that the road shocks have minimal effect on the occupants of the vehicle. Thus, the suspension system allows the vehicle to travel over rough uneven surfaces with minimum jerks. ] ■t Generally, a suspension system includes springs and dampers. The springs support the weight of the vehicle and absorb road shocks whereas the dampers help in controlling or dampening the spring action. In the absence of dampers, the springs experience prolonged oscillations. In such a case, springs keep the wheels of the vehicle in an unstable state after passing over bumps or holes. The damper acts as shock dampers, allowing the basic spring movement, but quickly dampening out the unwanted vibrations that follow. Conventionally, shock' absorbers are provided with non-linear rated springs to achieve progressive stiffeniiig. Progressive stiffening of a spring enables effective absorption of road shocks over a wider range, thereby providing the ride comfort to the passengers. The challenge associated with non-linear rated springs is that the extent of non-linearity achieved is limited primarily because of cost and manufacturing constraints. Further, non-linearity achieved is not very progressive due to the mechanical nature of the springs. Another challenge associated in providing the shock absorber with only non¬linear springs is that absorption and dissipation of energy released during the dampening process is not very effective arid efficient. This primarily happens because of the time lag of the damper in absorbing the energy and then releasing this absorbed energy to the surroundings. This results in momentary discomfort to the occupants of the vehicle. Aiding the shock absorber with a polyurethane helper spring though addresses this challenge but it substantially increases the manufacturing cost of the shock absorber. On the other hand, using a rubber helper spring does not reduce the time lag substantially and hence is not very effective in addressing the aforesaid challenge. Thus, in order to provide maximum comfort to the passengers of the vehicle, there is an urgent need to meet the aforesaid challenges keeping in mind the cost and durability of the shock absorber. SUMMARY: