試題詳解

3. A particle moves in the xy plane with a constant acceleration given by a = -m/s². At t = 0, its position and velocity are m/s, respectively. Here, t and j are unit vectors ng x and y directions, respectively. What is the distance from the origin to the pa 2.0 s?
(A) 6.4 m
(B) 10 m
(C) 8.9 m
(D) 2.0 m
(E) 6.2 m