We’re looking down on two positions (“initial” and “final”) of a spring-mass system that moves on a low-friction table,

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We’re looking down on two positions (“initial” and “final”) of a
spring-mass system that moves on a low-friction table, with the
left end of the spring tied to the stationary black ball, which is
free to turn. In the initial position the spring was relaxed, with
a length of di=di= 18 cm, and the sine of the
angle θiθi was 0.64. In the final position the
length of the spring
is df=df= 27.0 cm, |||p→f||||p→f| is 0.31 kg·m/s,
and the sine of the angle θfθf is 0.90. The mass of
the red ball is 0.7 kg.
What was the magnitude |||p→i||||p→i| of the initial
momentum?
What is the stiffness of the spring?