A 5-Kg Mass Slides Down a Smooth Incline $2$ the Angle of the Incline (Relative to the Horizontal)

Multiple Choice

A 5-kg mass slides down a smooth incline. The acceleration of the mass along the surface of the incline is 4.2 m/s $2$ . The angle of the incline (relative to the horizontal) is

A) 20°.
B) 16°.
C) 29°.
D) 25°.