## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)

(a) The block has a net force $F_x$ that points in the positive x-direction. Therefore, $a_x$ points in the positive x-direction. Therefore, the block speeds up from 0 to 1. (b) Although the magnitude of the force decreases, the block still has a net force $F_x$ that points in the positive x-direction. Therefore, $a_x$ points in the positive x-direction. Therefore, the block continues to speed up from 1 to 2.