Why must radio dishes be built so large?
What will be an ideal response?
Radio waves carry little energy, so a lot of them must be collected to give resolution and image quality comparable to light telescopes.
You might also like to view...
The ideal gas in a sealed container has its absolute temperature quadrupled. What happens to the average time between molecular collisions in the gas?
a. It stays the same. b. It decreases to half its original value. c. It decreases but not to half its original value. d. It increases.
A fastener bolt for the engine on a supersonic jet aircraft has a crosssectional area of 2.0 cm 2 and a length of 4.0 cm. The bolt part must be able withstand a tensile force of 10 × 104 N, and as a factor of safety this tensile force can produce a stress of no more than 50 percent of the tensile yield stress in the bolt. For sufficient resistance to fracture this critical bolt must have at least 15 percent strain to fracture. Because weight is critical for this jet aircraft design the maximum weight possible for this bolt is 40 g. The bolt is subject to temperatures up to 400°C (752°F).
To minimize the possibility of high temperature plastic strain the selected material should not be subject to more than 1/3 of its melting temperature. Of the materials covered in this chapter what would be the best material to select? Because this is a supersonic jet aircraft high priced materials can be utilized.
The angle that a swinging simple pendulum makes with the vertical obeys the equation ?(t) = (0.150 rad) cos[(2.85 rad/s)t + 1.66]. (a) What is the length of the pendulum?
A) 0.15 m B) 0.83 m C) 1.21 m D) 2.02 m E) It cannot be determined from the information given. (b) What is the mass of the swinging bob at the end of the pendulum? A) 2.85 kg B) 1.66 kg C) 0.454 kg D) 0.150 kg E) It cannot be determined from the information given.
What speed dilates 1.000 second into 70.71 seconds?
A) 0.9999c B) 0.9666c C) 0.9888c D) 0.9777c E) 0.8777c