1)  Consider two positively charged particles, one of charge q0 (particle 0) fixed at the origin, and another of charge q1 (particle 1) fixed on the y-axis at (0,d1,0). What is the net force F→ on particle 0 due to particle 1? Express your answer (a vector) using any or all of k, q0, q1, d1, i^, j^, and k^. 2)  Now add a third, negatively charged, particle, whose charge is −q2− (particle 2). Particle 2 fixed on the y-axis at position (0,d2,0). What is the new net force on particle 0, from particle 1 and particle 2? Express your answer (a vector) using any or all of k, q0, q1, q2, d1, d2, i^, j^, and k^.  3) Particle 0 experiences a repulsion from particle 1 and an attraction toward particle 2. For certain values of d1 and d2, the repulsion and attraction should balance each other, resulting in no net force. For what ratio d1/d2 is there no net force on particle 0? Express your answer in terms of any or all of the following variables: k, q0, q1, q2.

A 85 turn, 10.0 cm diameter coil rotates at an angular velocity of 8.00 rad/s in a 1.35 T field, starting with the normal of the plane of the coil perpendicular to the field. Assume that the positive max emf is reached first. (a) What (in V) is the peak emf? 7.17 V (b) At what time (in s) is the peak emf first reached? 0.196 S (c) At what time (in s) is the emf first at its most negative? 0.589 x s (d) What is the period (in s) of the AC voltage output? 0.785 S

A bobsled starts at the top of a track as human runners sprint from rest and then jump into the sled. Assume they reach 40 km/h from rest after covering a distance of 50 m over flat ice. a. How much work do they do on themselves and the sled which they are pushing given the fact that there are two men of combined mass 185 kg and the sled with a mass of 200 kg? (If you haven't seen bobsledding, watch youtube to understand better what's going on.) b. After this start, the team races down the track and descends vertically by 200 m. At the finish line the sled crosses with a speed of 55 m/s. How much energy was lost to drag and friction along the way down after the men were in the sled?