Aboxcar of length 9.9 m and height 2.4 m is at rest on frictionless rails. inside the boxcar (whose mass when empty is 3300 m) a tank containing 2100 m of water is located at the left end. the tank is 0.9 m long and 2.4 m tall. at some point the walls of the tank start to leak, and the water fills the floor of the boxcar uniformly. assume that all the water stays in the boxcar.

after all the water has leaked out what will be the final velocity of the boxcar?

what is the displacement of the boxcar 6 s after the water has settled in the bottom. (take positive displacement as being to the right.)

To understand the electric potential and electric field of a point charge in three dimensions consider a positive point charge q, located at the origin of three-dimensional space. throughout this problem, use k in place of 14? ? 0. part adue to symmetry, the electric field of a point charge at the origin must point from the origin. answer in one word. part bfind e(r), the magnitude of the electric field at distance r from the point charge q. express your answer in terms of r, k, and q. part cfind v(r), the electric potential at distance rfrom the point charge q. express your answer in terms of r, k, and q part dwhich of the following is the correct relationship between the magnitude of a radial electric field and its associated electric potential ? more than one answer may be correct for the particular case of a point charge at the origin, but you should choose the correct general relationship. a)e(r)=dv(r)drb)e(r)=v(r)rc)e(r)=? dv(r)drd)e(r)=? v(r)r