At one instant in time, a rock falling off a cliff experiences an upward force from air resistance at a magnitude of 10 n. the rock itself has a mass of 7 kg. what is the magnitude and direction of the acceleration of the rock at this instant? (take the magnitude of acceleration due to gravity to be 9.8 m/s2 and indicate direction by using a value for downward and a (+) value for upward.)
(hint: what is the net force acting on the rock? )
note: be careful entering your units! follow the instructions in the guide posted in the homework section!

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