51. The angle between the forces (x + y) and (x- y) if their resultant is /2 x² + y2 (A) 0°
(C) 60°
(B) 30°
(D) 90°

the answer to this is proletariats.

hope this : )

b. false

explanation:

suppose a rock in free fall is dropped off a cliff. after falling for 5 seconds, its speed would not be 100 m/s.