(2) According to the periodic formula of simple pendulum, the expression of gravity acceleration G is obtained, and the relationship between T 2 and T is analyzed. The gravity acceleration in Beijing is greater than that in Nanjing. According to the meaning of image slope, the expression of G is obtained.
(1) a. A simple pendulum is simple harmonic motion only when its swing angle is very small, and the swing angle of the simple pendulum cannot be too large, generally not more than 5, otherwise it is not simple harmonic motion. So, A is wrong.
B and c to reduce the influence of air resistance, the diameter of pendulum ball should be much smaller than the length of cycloid, and solid metal ball with high density should be selected as pendulum ball. Therefore, b and c are correct.
D, the pendulum length is equal to the length of the cycloid plus the radius of the pendulum ball. After the pendulum ball is suspended, measure the distance from the center of the pendulum ball to the suspension point with a meter ruler as the pendulum length. So, d is wrong.
So choose BC
(2) From the periodic formula of simple pendulum T=2π
L
G de
T2=
4π2
gauge length
According to mathematical knowledge, the slope of T2-L image is k=
4π2
g
Because the acceleration of gravity in Beijing is greater than that in Nanjing, we know that the graph corresponding to the experimental results of Peking University is B, which is obtained from the above formula: g=
4π2
k
So the answer is: BC, b,
4π2
k
,5,(20 12? In the experiment of measuring gravity acceleration with a single pendulum,
(1) The following measures are necessary or correct _ _ _ _. (Please fill in the serial number before the following measures)
A. In order to facilitate regular observation, the swing angle of a simple pendulum should be as large as possible.
The length of cycloid should be much larger than the diameter of pendulum ball.
C high-density solid metal balls should be selected for pendulum ball.
D, lay the pendulum ball and the cycloid flat on the table, measure the length from the center of the pendulum ball to a point o of the cycloid with a meter ruler as the pendulum length, and then take the point o as the suspension point.
(2) Two students explored the law of "the relationship between the period t and the pendulum length l of a simple pendulum" in Peking University and Southern University respectively. They changed the pendulum length several times, recorded several groups of data of pendulum length and period, and drew a T 2-L image, as shown in the figure. From this, it can be judged that the graph corresponding to the experimental results of Peking University is _ _ _ _ (fill in "A" or "B"). Students in Peking University worked out this chart.