試題詳解

3. The figure shows a block on a frictionless ramp; a cord attached to the block can pull on the block with a force parallel to the ramp. Here are three situations:

1. The block moves up the ramp with speed increasing at the rate of 2 m/s². 

2. The block moves down the ramp with speed decreasing at the rate of 2 m/s².

3. The block moves down the ramp with speed increasing at the rate of 2 m/s². Rank the three situations according to the tension in the cord, greatest first. () indicates a tie.

(A) 1, 2, 3
(B) 2, 1, 3
(C) (1,2), 3
(D) 1, (2,3)
(E) (2,3), 1