The vector position of a 3.70 g particle moving in the xy plane varies in time according to r1 = (3î + 3ĵ)t + 2ĵt^2 where t is in seconds and r with arrow is in centimeters. at the same time, the vector position of a 5.65 g particle varies as r2 = 3î − 2ît2 − 6ĵt.
(a) determine the vector position of the center of mass at t = 2.60.
(b) determine the linear momentum of the system at t = 2.60.
(c) determine the velocity of the center of mass at t = 2.60.
(d) determine the acceleration of the center of mass at t = 2.60.
(e) determine the net force exerted on the two-particle system at t = 2.60.

The dipole moment of the water molecule (h2o) is 6.17x10^-30 c.m. consider a water molecule located at the origin whose dipole moment p points in the +x-direction. a chlorine ion ( of charge-1.60x10^-19c , is located at x=3.00x10^-9m . assume that is much larger than the separation d between the charges in the dipole, so that the approximate expression for the electric field along the dipole axis can be used. a) find the magnitude of the electric force that the water molecule exerts on the chlorine ion. b) what is the direction of the electric force. -x-direction or +x-direction c) is this force attractive or repulsive?