Charge q1 = +3.60 nC is on the x-axis at x = 0 and an unknown charge q2 is on the x-axis at x = -4.00 cm. The total electric force
that q1 and q2 exert on a third charge q3 = +2.00 nC on the x-axis at
x = 4.00 cm is in the +x-direction and has magnitude 54.0 μN. Find (a) the
magnitude and direction of the force that q1 exerts on q3, (b) the magnitude
and direction of the force that q2 exerts on q3, and (c) the charge q2.

The magnitude of the amount of energy released by burning a fuel source, measured in energy per unit mass, is called its fuel value. note that the fuel value is the negative of the isobaric specific heat of combustion for the fuel. if all the energy obtained from burning 1.23 pounds of butane with a fuel value of 10.85 kcal/g is used to heat 128.0 kg of water at an initial temperature of 18.3 °c, what is the final temperature? note that 1 lb = 453.6 g.