Momentum is a product of mass and the velocity of a body. The initial momentum is always equal to the final momentum during collisions between two bodies.
Therefore; M1U1 +M2U2 = M1V1+ M2V2, where m1 is the mass of tracey and m2 is the mass of jonas, while u is the initial velocity and v is the final velocity.
(32 ×0)+ (45×0) = (32 × v1) + (45 × 0.50)
0 = 32V1 + 22.5
32 V1 = -22.5
V1 = - 0.703 ( negative indicates difference in direction)
There, Tracey's speed will be 0.703 m/s