2.1.1. In terms of the units mass M, length L, time T, and charge Q, find the units of the permittivity of free space ? ₀.

2.1.2. Find the force on a charge Q that is located at the point (6, 3). The charge has a value of Q = -3C. The other charges are: Q ₁(2, 0) = +2C, Q ₂(2, 3) = -4C, and Q ₃(2, 6) = -3C. All dimensions are in meters.

2.1.3. For the charges given in Problem 2, find the force on the charge Q ₂.

2.1.4. Four equal charges ( Q) are placed at the corners of a square whose dimensions are ( a a). Find the magnitude of the force on one of the charges.

2.1.5. Two small plastic balls, each with equal values of charge Q and mass M are constrained to slide on an insulating string. Find the separation of the two charges if the lower charge is constrained to one location on the string.

2.2.1. In terms of the units mass M, length L, time T, and charge Q, find the units of the electric field E.

2.2.2. Find the electric field at the point P that is located at (5, 1) due to the charges Q ₁(1, 4) = +2C and Q