# Search results

1. ### Remote Internet voting security flaw?

Hi guys, Traditional voting via paper ballots at polling stations, meant that each individual was free to vote for his candidate in complete privacy. A father could vote for a separate candidate and a son for another candidate. So I was wondering is there any way in which to ensure similar...
2. ### Protocols insecure against Replay Attack

Homework Statement Determine which of the following protocols are insecure against replay attack , and explain why: (a) A → B : username, password (b) A → B : username, h(timestamp, password) (c) A → B : username, timestamp, h(password) (d) A → B : username...
3. ### Measuring the size of a molecule

Hi, Homework Statement I am trying to determine the size of a molecule..by doing the oil drop experiment where we drop a tiny droplet of oil on water covered with a thin layer of powder...and then make calculations based on the diameter of the circle... the droplet forms in oil. The Attempt...
4. ### Measuring speed of sound in air

Hi. I have been given the task to measure the speed of sound in air. The materials available are: 1. Microphone 2. Signal Generator 3. Amplifier 4. Digital Oscilloscope I have looked through google and the simplest exp involves a loudspeaker as well. However I dont have one...
5. ### Newtons third law of motion

Homework Statement A particle of mass 4kg is being towed at a constant speed up a rough plane inclined at 30 degrees to the horizontal by a force 4g N acting parallel to the slope. At the top of the slope the particle moves onto a rough horizontal slope with the same coefficient of friction...
6. ### A doubt about RC circuits

In an RC circuit shown below, with the switch closed after a long time, when the capacitor is charging, there is a current across the capacitor given by Initial current x e ^ (-t/RC)... Is this current....the current supplied by capacitor to the rest of circuit, or simply the current across...
7. ### Engineering Solving an RC circuit question using Superposition

Hello, The circuit attached below is from Richard Dorfs Intro to Electric Circuits book. The switch is shut for a long time and opened at t=0. The question asks to find the i(t) across R11, which they use nodal analaysis and find it to be 66.67 - 16.666 e^{-t/120} micro Amps, where 66.67 micro...
8. ### Complex Numbers: Finding the least value of |z-w|

Homework Statement The complex numbers, z and w satisfy the inequalities |z-3-2i|<=2 and |w-7-5i|<=1 Find the least possible value of |z-w| Homework Equations No clue at all. The Attempt at a Solution Since its |z-w| i figured that the least possible value will only be...
9. ### Two Parallel Voltage sources and KVL

Hi, I understand that you cannot apply KVL to voltage sources connected in parallel, unless both voltage sources are the same, as this violates KVL. However, I want to know why? Just a simple 2-3 line explanation will suffice. Regards