試題詳解

74. Suppose that a car traveling to the west (the -x direction) begins to slow down as it approaches a traffic light. Which statement concerning its acceleration in the x direction is correct?
(A) Its acceleration is positive but its velocity is negative.
(B) Its acceleration is negative but its velocity is positive.
(C) Both its acceleration and its velocity are positive.
(D) Both its acceleration and its velocity are negative.