The voltage drop across the resistor is the product of the (constant) resistance r of the resistor, and the current i(t) passing through the resistor. the voltage drop across a capacitor is equal to q c , where q(t) is the charge on the capacitor, and the constant c is the capacitance of the capacitor. across a voltage source (typically a battery or a power supply), the voltage increases by v(t) , so the voltage drop is is −v(t) . the current passing through the resistor and the charge on the capacitor are related by the equation i = dq/dt . write a differential equation for the charge q(t) on the capacitor as a function of time. your answer should depend on q, v , and the constants r and c , but not on i . in your answer, write just q and v for the functions q(t) and v(t) . remember to insert a space or explicitly type "*" between two letters to indicate multiplication.

Classify the following soils according to the uscs classification system. provide appropriate uscs designations. a) this sample of well-graded gravel with sand was obtained from a large earthen dam in vancouver, canada. the sample has 73% fine to coarse sub-angular gravel, 25% fine to coarse sub-angular sand and 2% fines. the maximum size of the particles is 75 mm. the coefficient of curvature is 2.7, while the uniformity coefficient is 12.4. b) this dark brown and wet soil with a “strong organic odor” has 100% passing the no. 200 sieve. the liquid limit of the material is 32% when not dried and is 21% when oven-dried. the plastic index is 21% when not dried. c) this sand has 61% predominantly fine sand, 23% silty fines, and 16% fine sub-rounded gravel size. the maximum size is 20 mm. the liquid limit is 33% and the plastic limit is 27%. d) this soil has 74% fine to coarse sub-angular reddish sand and 26% organic and silty dark brown fines. the liquid limit is 37% when not dried and is 26% when oven dried. the plastic index is 6% when not dried.

The passage that directs air to the lungs is called a. diaphragm. b. larynx. c. bronchi. d. pharynx.

If a negatively charged particle is placed at rest in an electric potential field that increases in the positive x-direction, what will the particle do? a. accelerate in the positive x-direction b. remain at rest c. accelerate in the negative x-direction