Two objects are held close to each other with a compressed spring between them. When the spring is released, one object moves off with a speed of 0.63 m/s, and the other object moves off with a speed of 0.45 m/s. If the faster object has a mass of 0.15 kg, what is the mass of the slower
object?
(A) 0.15 kg (B) 0.21 kg (C) 0.30 kg (D) 0.37 kg
. For the same object as the previous problem, what is the total momentum of both objects just after the spring is released?
(A) 0 kg • m/s (B) 0.095 kg • m/s (C) 0.19 kg • m/s (D) 0.38 kg • m/s

Emmy kicks a soccer ball up at an angle of 45° over a level field. she watches the ball's trajectory and notices that it lands, two seconds after being kicked, about 20 m away to the north. assume that air resistance is negligible, and plot the horizontal and vertical components of the ball's velocity as a function of time. consider only the time that the ball is in the air, after being kicked but before landing. take "north" and "up" as the positive ‑ and ‑directions, respectively, and use ≈10 m/s2 for the downward acceleration due to gravity.