Aman walks on the edge of a circular disk with the radius 100 m towards the center. the man walk at constant speed of 1 m/sek. the disk rotates anticlockwise around its center so it goes one circle per hour. (hint: let the angular velocity be for example ω = 2π/klst =2π/3600sek and dont put the numbers into the calculations until in the end.)
(a) describe with parameterization the movement of the man seen from someone who is standing above the disk. let the center of the circle be in (0,0) and the man start the walk in the point (x0,y0) = (0,100m) at the time t = 0. the coordinate system does not rotate with the disk.
(b) calculate the speed vector of the man and the speed seen from someone who is watching from above the disk.

One kind of e-book display consists of millions of very small spheres that float in a thin fluid layer between two conducting transparent plates. each sphere is black on one side and white on the other, and possesses an electric dipole moment directed from the white side to the black. when an electric field is applied between the plates, the spheres rotate so that their dipole moment lines up with the field. depending on the fields direction, either the black or the white sides of th espheres can be made visible. the dipole moment of the spheres can be modeled as two opposite charges of magnitude 3.5 x 10^-15 c, separated by a distancce of 100 micrometers (um). what is the maximum possible torque on a sphere if the electric field between the transparent plates is 4.0 x 10^5 n/c