A refracting telescope has an eyepiece of focal length -80 mm and an objective of focal length 36 cm. What is the magnification of this instrument?
What will be an ideal response?
4.5
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The center of mass of a system of particles (or objects) with total mass M moves like a single particle of mass M acted upon by the same net external force
Indicate whether the statement is true or false
Two parallel wires carry a current I in the same direction. Midway between these wires is a third wire, also parallel to the other two, which carries a current 0.5 I, but in the direction opposite from the first two wires. In which direction are the net forces on the outer wires?
a. Since the net forces are zero, there is no direction. b. Both forces are toward the center wire. c. Both forces are away from the center wire. d. Both forces on the two wires are in the same direction in space.
An intercooler of an air compressor is to use a finned flat tube heat exchanger as shown in Figure 9-29. Compressed air at 100 psia, 130ºF passes through the tubes at 100 ft/s and air at 14.7 psia, 70ºF, and 100 ft/s passes around the tubes. Determine the convective heat transfer coefficient, the friction factor for the cooling air outside the tubes, and the overall convective heat transfer coefficient for the intercooler. Assume the inside dimensions of the flattened tubes are 0.105 in by 0.865 in.
If a current of negative charge flows in a circle in the direction of one's curled fingers of the right hand, the resulting magnetic field would be in the direction
A. opposite to the thumb of the right hand. B. of the right index finger. C. of due north. D. of the thumb of the right hand.