This is a representation of a plastic bag being stretched.Which statement best describes what is happening in the figure?
A)Molecular chains shift from a random orientation to align parallel to each other in the direction of the pulling force
B)During the pulling,the mixed-up polymer chains cross link to make the polymer stronger
C)The pulling force creates branches,causing a switch from high density to low density polymer
D)It is only a temporary distortion;once the pulling force stops,the plastic snaps back to the original orientation

Question

This is a representation of a plastic bag being stretched.Which statement best describes what is happening in the figure? 
A)Molecular chains shift from a random orientation to align parallel to each other in the direction of the pulling force 
B)During the pulling,the mixed-up polymer chains cross link to make the polymer stronger 
C)The pulling force creates branches,causing a switch from high density to low density polymer 
D)It is only a temporary distortion;once the pulling force stops,the plastic snaps back to the original orientation

Quizplus · Accepted Answer

When a plastic bag is stretched, the molecules within the polymer chains start to align themselves parallel to the direction of the pulling force. As a result, the bag becomes thinner and longer. However, the stretching is only temporary, and unless the plastic is heated and cooled in this new orientation, it will return to its original shape once the force is released. Cross-linking (B) and branching (C) can occur in some types of plastic, but they are not the primary mechanism at work in plastic stretching. Option D is also incorrect as the stretching is not a temporary distortion.

This Is a Representation of a Plastic Bag Being Stretched