Short Answer

$$\text { Find } \mathbf { r } ^ { t } ( t ) \text { and } \mathbf { r } ^ {tt } ( t ) \text { for } \mathbf { r } ( t ) = 10 t \mathbf { i } + 7 t ^ { 2 } \mathbf { j } + 5 t ^ { 3 } \mathbf { k }$$