So the answer is 0.39.

(2) As can be seen from the figure, the intercept of the vertical axis corresponds to the square of the velocity of the hitting point A, so there is: V2A = 0.25m2/S2, so there is: VA = 0.50m/s. 。

So the answer is: 0.50(0.48-0.52).

(3) According to the kinetic energy theorem: w = 12mv2t? 12mv20, we can get: v2t = v20+2wm, so the slope of the image is: k = 2m, and the value of the substituted data is: m = 0.30kg 。

So the answer is: 0.30 (0.28-0.32).