If R(t) Is the Position Vector of a Particle in the Plane

question 67

Multiple Choice

If r(t) is the position vector of a particle in the plane at time t, find the indicated vector.
-Find the velocity vector.
$\mathbf { r } ( \mathrm { t } ) = \left( - 8 \mathrm { t } ^ { 2 } - 3 \right) \mathbf { i } + \left( \frac { 1 } { 9 } \mathrm { t } ^ { 3 } \right) \mathbf { j }$

• A) \(v = ( - 16 ) i + \left( \frac { 2 } { 3 } t \right) j\)
• B) \(\mathbf { v } = ( - 16 \mathrm { t } ) \mathbf { i } + \left( \frac { 1 } { 3 } \mathrm { t } ^ { 2 } \right) j\)
• C) \(\mathbf { v } = ( - 16 \mathrm { t } ) \mathbf { i } - \left( \frac { 1 } { 3 } \mathrm { t } ^ { 2 } \right) \mathbf { j }\)
• D) \(\mathbf { v } = \left( \frac { 1 } { 3 } \mathrm { t } ^ { 2 } \right) \mathbf { i } + ( - 16 \mathrm { t } ) \mathbf { j }\)

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