Calculate the magnitude of the acceleration of a sled that is heading down a 39° slope (one that makes an angle of 39° with the horizontal). the coefficient of kinetic friction on ice is μk = 0.100. (take the x direction to be parallel to and down the slope and the y direction to be perpendicular to the slope.)

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

The energy of a photon is equal to (what) times (what) of the photon.

Roger pushes a box on a 30° incline. if he applies a force of 60 newtons parallel to the incline and displaces the box 10 meters along the incline, how much work will he do on the box? a. 5.2 × 102 joules b. 6.0 × 102 joules c. -5.2 × 102 joules d. -6.0 × 102 joules