Q1. A 0.0150-m wire oriented parallel between the poles of an electromagnet carries a direct current of 9.5 A. The angle between the direction of current and that of magnetic field is 25.0° as shown. If the magnetic field strength is 0.845 T, what is magnitude and direction of the magnetic force on the wire between the poles?

Q2. Think about a motor that exerts a constant torque of 25.0 to a horizontal platform whose moment of inertia is 50.0. Presume that the platform is initially at rest and the torque is applied for 12.0. Neglect friction.

What is rotational kinetic energy of the platform at the end of the process described above?

Q3. Four point charges have equal magnitudes. Three are positive, and one is negative (order is A = +, B= +, C=+, D = -). They are fixed in place on the same straight line and adjacent charges are equally separated by a distance d. Consider the net electrostatic force acting on each charge. Compute the ratio of the largest to the smallest net force.