Solve the Problem B) C) D)

Multiple Choice

Solve the problem. Unless stated otherwise, assume that the projectile flight is ideal, that the launch angle is measured from the horizontal, and that the projectile is launched from the origin over a horizontal surface
-An ideal projectile is launched from the origin at an angle of α radians to the horizontal and an initial speed of 175 ft/sec. Find the position function r(t) for this projectile.

A) $\mathbf { r } ( \mathrm { t } ) = ( 175 \mathrm { t } \sin \alpha ) \mathbf { i } + \left( 175 \mathrm { t } \cos \alpha - 16 \mathrm { t } ^ { 2 } \right) \mathbf { j }$
B) $\mathbf { r } ( \mathrm { t } ) = ( 175 \mathrm { t } \cos \alpha ) \mathbf { i } + \left( 175 \mathrm { t } \sin \alpha - 16 \mathrm { t } ^ { 2 } \right) \mathbf { j }$
C) $\mathbf { r } ( \mathrm { t } ) = \left( 175 \mathrm { t } \sin \alpha - 16 \mathrm { t } ^ { 2 } \right) \mathbf { i } + ( 175 \mathrm { t } \cos \alpha ) \mathbf { j }$
D) $\mathbf { r } ( \mathrm { t } ) = \left( 175 \mathrm { t } \cos \alpha - 32 \mathrm { t } ^ { 2 } \right) \mathbf { i } + ( 175 \mathrm { t } \sin \alpha ) \mathbf { j }$