Need Help?

Subscribe to Physics 2

Subscribe
  • Notes
  • Comments & Questions

$$
\begin{array}{l}{\text { The current in a wire varies with time according to the }} \\ {\text { relationship } I=55 \mathrm{A}-\left(0.65 \mathrm{A} / \mathrm{s}^{2}\right) t^{2} . \text { (a) How many coulombs }} \\ {\text { of charge pass a cross section of the wire in the time interval }} \\ {\text { between } t=0 \text { and } t=8.0 \mathrm{s} ?(\mathrm{b}) \text { What constant current would }} \\ {\text { transport the same charge in the same time interval? }}\end{array}
$$

$$
I=\frac{d Q}{d t} \longrightarrow d Q=I . d t
$$

(a) $$
Q=\int_{0}^{8}\left(55-0.65 t^{2}\right) d t = \left[55 t-0.217 t^{3}\right]_{0}^{8}
$$

$$
\rightarrow Q=55(8)-(0.217)(8)^{3}=330 c
$$

$$
I=\frac{Q}{t}=\frac{330}{8}=41 . A
$$

No comments yet

Join the conversation

Join Notatee Today!