Question

When fragments deposited by mass movement are at the ________, they are in a fine balance

between the pull of gravity and the cohesion and friction of the rock material.
A) size of clay
B) bottom of the talus slope
C) terminal velocity
D) angle of repose
E) top of the hill

Answer 1

The fine balance between the pull of gravity and material cohesion and friction occurs at the angle of repose, which varies by material type.

Step-by-step explanation:

When fragments deposited by mass movement are at the angle of repose, they are in a fine balance between the pull of gravity and the cohesion and friction of the rock material. The angle of repose is defined as the steepest angle at which loose material remains stable and will therefore not slide or flow. It is where the force due to gravity, which tends to cause the material to slide down the slope, is exactly balanced by the forces of cohesion and friction between the particles, which resist motion. The specific angle will vary depending on the type of material; for example, sandstone has an angle of repose of about 30°, while shale's is higher, often exceeding 40°.