A Particle Moves with Position Function $\mathbf { r } ( t ) = \left( 21 t - 7 t ^ { 3 } - 5 \right) \mathbf { i } + 21 t ^ { 2 } \mathbf { j }$

question 14

Multiple Choice

A particle moves with position function $\mathbf { r } ( t ) = \left( 21 t - 7 t ^ { 3 } - 5 \right) \mathbf { i } + 21 t ^ { 2 } \mathbf { j }$ . Find the tangential component of the acceleration vector.

• A) \(a _ { T } = 5 t\)
• B) \(a _ { T } = 542 t\)
• C) \(a _ { T } = 42 t + 5\)
• D) \(a _ { T } = - 55 t\)
• E) \(a _ { T } = 42 t\)

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Definitions:

Ebbinghaus

A psychologist known for his research on memory and the forgetting curve, the decline of memory retention over time.

Retrieval Period

The timeframe during which a memory or piece of information is recalled or retrieved from the storage after learning.

Decay Theory

A theory of forgetting that proposes that memories may fade or erode over time in the absence of rehearsal or usage.

Sensory Memory

The very first system in memory, in which raw information from the senses is held for a very brief period of time.