Introduction:
In order to determine the stability of 2-methyl-1-butene and 2-pentene, we need to analyze their molecular structures and consider the factors that influence stability, such as hyperconjugation and steric hindrance.

Analysis:
Molecular Structures:
1. 2-Methyl-1-butene: This compound has a double bond between the first and second carbon atoms, with a methyl group attached to the second carbon atom.
2. 2-Pentene: This compound also has a double bond between the first and second carbon atoms, but it lacks any additional substituents.

Hyperconjugation:
Hyperconjugation occurs when an adjacent σ-bonded atom or group donates electron density into an empty or partially filled π-orbital, resulting in increased stability. The more hyperconjugative structures a compound can have, the more stable it is.

2-Methyl-1-butene:
- The presence of the methyl group in 2-methyl-1-butene allows for hyperconjugation between the σ-bonded C-H bonds and the adjacent π-orbital of the double bond.
- This compound can have two hyperconjugative structures, leading to increased stability.

2-Pentene:
- 2-Pentene lacks any additional substituents, so it does not have any hyperconjugative structures.

Steric Hindrance:
Steric hindrance refers to the repulsion between atoms or groups that are in close proximity to each other. Bulky substituents can lead to increased steric hindrance, reducing stability.

2-Methyl-1-butene:
- The methyl group in 2-methyl-1-butene is relatively small and does not cause significant steric hindrance.

2-Pentene:
- 2-Pentene lacks any additional substituents, so there is no steric hindrance in this compound.

Conclusion:
Based on the analysis of the molecular structures, hyperconjugation, and steric hindrance, we can conclude that 2-methyl-1-butene is more stable than 2-pentene. The presence of the methyl group in 2-methyl-1-butene allows for hyperconjugation, contributing to increased stability. Additionally, there is no significant steric hindrance in either compound.