Name:

PHYSICS 232
Midterm 1, February 27 , 1998, 5:30pm-6:45pm
Instructor: P. Q. Hung

25 points for each problem. READ the problems carefully. SHOW YOUR WORK. DO NOT JUST write the answers down and *PLEASE* DO NOT SCRIBBLE. ANSWERS WITHOUT EXPLANATION WILL BE GIVEN NO CREDIT. CIRCLE YOUR ANSWERS!

Useful formulas (not necessarily applied to all problems below):

$\vec{F} = m\vec{a}$

$x = x_{0} + v_{0x} t + \frac{1}{2} a_{x} t^2$

$y = y_{0} + v_{0y} t + \frac{1}{2} a_{y} t^2$

$F = k \frac{q_{1} q_{2}}{r^2}$

$\vec{E} = k \frac{q}{r^2} \hat{r}$

$Q = \int \rho dV$. For $\rho = \rho (r)$, $dV = 4\pi r^2 dr$

$V= k \frac{q}{r}$

$V_B - V_A = -\int_{A}^{B} \vec{E} \cdot d\vec{s}$

$\Phi = \oint \vec{E} \cdot d\vec{A} = 4 \pi k Q$

$C= \frac{Q}{V}$

$E = \frac{\sigma}{\epsilon_0}$

$C = \epsilon_0 \frac{A}{d}$

$I = \frac{dQ}{dt}$, V= I R

$U = \frac{1}{2} Q V = \frac{1}{2} C V^2$

I = nqv_d A

P= I²R = V²/R

$k = 8.99 \times 10^9 N\cdot m^2/C^2$

$\epsilon_0 = 1/4\pi k = 8.85 \times 10^{-12} C^2/N\cdot m^2$

$e= 1.6 \times 10^{-19} C$

$\int x^n dx = \frac{x^{n+1}}{n+1}$