In this diagram, heat energy is being added over time. The vertical axis shows an increase in temperature, and the horizontal axis shows the passage of time. Which point is the solid melting at in the diagram? A B C D

Point charges q1 = 51 µc and q2 = −27 µc are placed 1.0 m apart, with q2 on the right. what is the force (in n) on a third charge q3 = 19 µc placed midway between q1 and q2? (assume the positive direction is to the right. indicate the direction with the sign of your answer.)