(1) The pendulum length is equal to the sum of the length of the cycloid and the radius of the pendulum ball. The way to measure the pendulum length is to measure the diameter of the ball. After the pendulum is fixed, let the ball droop naturally, measure the length of the cycloid with a scale and add the radius of the ball. So d is right, and A, B and C are wrong.

Therefore, choose: d.

(2) According to T=2πLg, T2 = 4π 2LG, the slope of the graph is 4π2g, and the gravitational acceleration of Peking University is greater than that of HKU. Because the slope of Figure B is small, the gravity acceleration corresponding to Figure B is large, and the experimental results measured by Peking University students correspond to Figure B. 。

According to the image, if the period of A is 43s and the period of B is 2s, then the ratio of the periods of A and B is 2: 3 and the pendulum length L=gT24π2, then the ratio of the pendulum lengths of A and B is 4: 9.

So the answer is: (1)D? ②B，49。