Figure 13 displays the voltage V across a capacitor as a function of time while the capacitor

Question:

Figure 13 displays the voltage V across a capacitor as a function of time while the capacitor is being charged. Estimate the rate of change of voltage at t = 20 s. Indicate the values in your calculation and include proper units. Does voltage change more quickly or more slowly as time goes on? Explain in terms of tangent lines.

4 3 2 1 V (V) 10 20 30 40 -t (s)