If ř (t) = t^3i - 2tj + (t^2-2t)k Define velocity and acceleration. If the velocity vector is given on (x, y) plane at time t, define v(t) and a(t) at time t.

The answer is 4f======since electrostatic force is given by    we let f be the electrostatic force when  r = 1 m    if we let  denote the electrostatic force when the distance is decreased so that r = 0.5m, then    we established earlier that f = kq₁q₂. therefore    the force will now be 4f.

The fuzzy edges of shadows are a result of  diffraction 

(5.8/6.8)x100% = 85.3%