Nhận biết (M1)

While researching a topic, a student has taken the following notes:

• The typical resting viscosity of oobleck (cornstarch mixed with water) is 5–100 centipoise (cP).

• Oobleck increases in viscosity (becomes thicker) when stirred.

• The typical resting viscosity of fruit jam is 5,000–10,000 (cP).

• Fruit jam decreases in viscosity (becomes thinner) when stirred.

• A fluid is Newtonian if its viscosity remains stable under shear (mechanical force such as being stirred or squeezed).

• A fluid is non-Newtonian if its viscosity changes under shear.

The student wants to contrast how shear affects fruit jam and oobleck. Which choice most effectively uses relevant information from the notes to accomplish this goal?

• A.

  Though the viscosities of both oobleck and fruit jam change under shear, oobleck’s typical resting viscosity (5–100 cP) is lower than that of fruit jam (5,000–10,000 cP).

• B.

  Fruit jam is non-Newtonian, meaning its viscosity decreases under shear; oobleck, by contrast, increases in viscosity.

• C.

  Fruit jam becomes thinner when stirred, while oobleck becomes thicker.

• D.

  Oobleck has a much lower resting viscosity than fruit jam but becomes thicker under shear.