A physics interest group uses the digital experimental system in the school laboratory to explore the relationship between centripetal force and angular velocity and radius when an object moves in a circular motion. (1) When drawing after the tracing point, pay attention to make the tracing point fall on the same curve as far as possible, and make the points that cannot fall on the curve evenly distributed on both sides, as shown in the figure:

(2) Students in the interest group guess that F is proportional to ω2 by observing the images. Through further transformation, they can determine whether their guess is correct by drawing an image of the relationship between F and ω2. If the guess is correct, the relationship between f and ω2 should be an inclined straight line.

(3) After determining F∑ω2, they adjusted the radius r of the circular motion of the weight to 0.04m and 0. 12m respectively, and got two F-ω images. They put the images obtained from the three experiments in a coordinate system, as shown in Figure B. By comparing, analyzing and discussing the three images, they get F ∑Ωr..

(4) The mathematical relationship between centripetal force F and angular velocity ω and radius r is F=kω2r, which is substituted into the coordinate values of any point in Figure A, such as A (20, 1.2) with a radius of 0.08m,

de: 1.2n = K202(ω/rad)20.08m

Solution: k=0.038kg

So the answer is: as shown in Figure F and ω2, make an auxiliary line parallel to the longitudinal axis, and observe whether the ratio of the force value at the intersection with the image is 1: 2: 3, 0.038 kg.