Molecular weight plays a significant role in determining the physical properties of polymers, including tensile strength and flexibility. Polymers are made up of long chains of repeating units called monomers. The molecular weight of a polymer is a measure of the size and mass of these chains.1. Tensile strength: Tensile strength is the ability of a material to withstand a pulling force without breaking. As the molecular weight of a polymer increases, the tensile strength generally increases as well. This is because longer polymer chains have more entanglements and stronger intermolecular forces, such as van der Waals forces, which hold the chains together. These interactions make it more difficult for the chains to slide past one another, resulting in a stronger material that can withstand greater forces.2. Flexibility: Flexibility is the ability of a material to bend or deform without breaking. In general, polymers with lower molecular weights tend to be more flexible than those with higher molecular weights. This is because shorter polymer chains have fewer entanglements and weaker intermolecular forces, allowing them to slide past one another more easily. As a result, the material can bend and deform more readily without breaking.However, it is essential to note that the relationship between molecular weight and physical properties is not always linear, and other factors, such as the polymer's chemical structure, degree of crystallinity, and processing conditions, can also influence its properties. In some cases, increasing the molecular weight may lead to a decrease in flexibility or tensile strength, depending on the specific polymer and its characteristics.