Modern Physics
Questions & Answers
8. Imagine for a minute that the moon is held in its orbit about the Earth by electrical forces rather than by gravitation. What is the necessary electrical charge -Q that would be on the Earth and +Q that would be on the moon to hold the moon in a circular orbit of 27.3 days? The Earth-moon distance is 384,000 km and the mass of the moon is 7.35 x 1022 kg.
For each of the following maximum depths, determine the minimum P.R.P. and maximum P.R.F.: 1. 5cm 2. 8cm 3. 12cm 4. 10cm
Calculate the frame rate (in Hz) for each of the following conditions: 1. P.R.F. = 4 kHz, lines per frame = 120, 1 focal zone: 2. P.R.P. = 200 us, lines per frame = 200, 2 focal zones: 3. Max. depth = 11 cm, lines per frame = 140, 2 focal zones:
How many possible combinations are there in each system: 2 bit: 3 bit: 6 bit: 8 bit: 9 bit: 10 bit:
For each of the following, name the special feature you would use: 1. You want to decrease compression only in areas very close to a border, in order to make these borders more easily visible. 2. You want to add more scan lines to your image by sliding the transducer along the scan plane (making your picture much wider). 3. You want to change the shades of gray on your frozen picture to shades of magenta (or some other color). 4. You want the machine to automatically fill in the blank areas between diverging scan lines of your sector image with "fake" pixels. 5. You want to make your gray-scale imaging sensitive enough to pick up echoes from red blood cells as they move through the vessels. 6. You want the machine to take multiple frames and average them together in order to cancel out the random, background noise. 7. You want to enlarge a certain area of the anatomy by concentrating more scan lines in just that one selected area and filling the screen with just these lines (must be done before freezing the image). 8. Instead of seeing a 2-D picture of the anatomy, you want a graph showing the exact amplitudes or intensities of all the echoes in just one scan line.
Physics Quiz #3 Review (Chapter 4 - Part 2) 19. Which function of the machine is responsible for putting all of the scan line data together in preparation for frame (image) production? Where in the instrument does this happen?
1) State Hooke's law and write the equation for the spring system upto the limit of proportionality.
2) Write the mathematical relationship between Mass (in kg), Weight (in N) and acceleration due to gravity (g).
3) Sketch and label a graph of extension (∆I) against Weight (W) including the limit of proportionality and beyond this point.
