Angie Says That an Object Is in Equilibrium If the Net

question 17

Multiple Choice

Angie says that an object is in equilibrium if the net torques about the center of mass is zero. Robbie says that an object is in equilibrium if the sum of external forces is zero. Which one, if either, is correct?

• A) Both are correct: an object is in equilibrium if either condition holds.
• B) Neither is correct: both conditions must hold simultaneously.
• C) Neither is correct: the net external force and the net external torque about any axis must be zero.
• D) Neither is correct: an object is in equilibrium only if its velocity is zero in all coordinate systems.
• E) Both are correct: if the sum of the external forces is zero, the net torque about any axis is automatically zero, and vice versa.

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Definitions:

Landslide

The sudden and rapid movement of a large amount of earth material, such as rock and soil, downslope due to gravity.

Unconformity

A surface of erosion or non-deposition that separates younger strata from older rocks, indicating a gap in the geologic record.

Conglomerate

A conglomerate is a coarse-grained sedimentary rock composed of rounded fragments larger than 2 mm in diameter, embedded in a matrix of finer particles and cement.

Shale Layer

A shale layer is a sedimentary rock formation characterized by fine-grained clay particles, often found in various geological strata and known for being a source of oil and natural gas through hydraulic fracturing.