Physics, 30.06.2019 03:30 pedrojsq271
Arianna finds some fossil bones whip digging in her backyard. could they be dinosaur bones? using carbon dating, she determines that 3% of the original radioactive carbon-14 is still radioactive. (the reef has decayed to nitrogen-14.) approximately how many half-lives have occurred? the half-life of carbon-14 is 5,730 years. this means that the animal died approximately years ago.
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Physics, 21.06.2019 18:10
Scientists use laser range-finding to measure the distance to the moon with great accuracy. a brief laser pulse is fired at the moon, then the time interval is measured until the "echo" is seen by a telescope. a laser beam spreads out as it travels because it diffracts through a circular exit as it leaves the laser. in order for the reflected light to be bright enough to detect, the laser spot on the moon must be no more than 1.0 km in diameter. staying within this diameter is accomplished by using a special large-diameter laser. part a if λ = 540nm , what is the minimum diameter of the circular opening from which the laser beam emerges? the earth-moon distance is 384,000 km. express your answer to two significant figures and include the appropriate units.
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Physics, 22.06.2019 00:50
Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 10.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.90 m/s; (b) he is then lifted at the constant speed of 4.90 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 68.0 kg rescue by the force lifting him during each stage?
Answers: 1
Physics, 22.06.2019 01:30
John throws .4 kg ball with velocity of 18 m/s. hits .2 kg bottle and bottle flies 25 m/s. how fast is ball traveling after hitting the bottle?
Answers: 1
Arianna finds some fossil bones whip digging in her backyard. could they be dinosaur bones? using c...
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