The vector position of a 3.65 g particle moving in the xy plane varies in time according to the following equation.

r1 = <(3i+3j)t + 2jt^2>
At the same time, the vector position of a 5.60 g particle varies according to the following equation.

r2 = <3i - 2it^2 - 6jt>

For each equation, t is in s and r is in cm. Solve the following when t = 2.90
(a) Find the vector position of the center of mass.
i-hat__________ cm
j-hat___________cm

(b) Find the linear momentum of the system.
i-hat___________ g-cm/s
j-hat____________g-cm/s

(c) Find the velocity of the center of mass.
i-hat_________cm/s
j-hat__________ cm/s

(d) Find the acceleration of the center of mass.
i-hat____________cm/s2
j-hat_____________cm/s2

(e) Find the net force exerted on the two-particle system.
i-hat___________ μN
j-hat___________μN

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Maybe someone could just explain to me how to solve for each part because I'm thoroughly confused. THANK YOU.