Two thin lenses in combination are placed in contact with each other along a common axis. They have powers of 70 and –20 diopters, respectively. What is their combined power?
a. 25 diopters
b. 50 diopters
c. 90 diopters
d. –25 diopters
e. 70 diopters
b
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A car enters a level, unbanked semi-circular hairpin turn of 100-m radius at a speed of 28 m/s. The coefficient of friction between the tires and the road is ? = 0.800. If the car maintains a constant speed of 28 m/s, it will
A. attempt to dig into the road surface. B. tend to veer toward the center of the semicircle. C. arrive safely at the end of the semicircle. D. tend to veer toward the outside of the circle. E. veer toward the center for the first quarter-circle, then veer toward the outside for the second quarter-circle.
The Jovian planets
a. are composed mainly of hydrogen and helium. b. have no solid surface. c. have rings. d. all of these.
A plate sliding into a subduction zone can trigger ____
a. midocean rise b. cratering c. volcanism d. hurricanes e. erosion
A projectile is launched with speed v at an angle ?, the angle being less than 45º. What other angle would give the same range for this projectile launched at the same speed v?
a. 2? b. 0.5? c. 90° – ? d. 90º – 0.5?