<h3><u>Answer;</u></h3>
Carbon-14 levels in a sample are undetectable after approximately 9 half lives
<h3><u>Explanation;</u></h3>
- <em><u>The half life of Carbon-14 is 5,730 years . Half life is the time taken by a radioactive material to decay by half of its original mass. Therefore, it would take a time of 5730 years for a sample of 100 g of carbon-14 to decay to 50 grams</u></em>
- <em><u>A period of 50,000 years, is equivalent to; </u></em>
<em><u> 50,000÷5,730 </u></em>
<em><u>= 8.73 half lives</u></em>
<em>Which is approximately equal to 9 half lives.</em>
- Therefore, if the age of an object older than 50,000 years cannot be determined by radiocarbon dating, then <em><u>Carbon-14 levels in a sample are undetectable after approximately 9 half lives</u></em>.
Answer:
D- Strong and gravitational
Explanation:
Answer:
work being done on an object.
Answer. A. A man pushes a couch across the room
diagram identifies an axle:
Answer: B. Z
simple machine described as a shaft at the center of a wheel:
Answer: D. Wheel and axle
Type of lever:
A. a catapult
82 ÷ 6.5 = 12.615384615384... repeating
round = 12.6
12.6 · 6.5 = 81.9
round = 82
She went an average of 12.6 km an hour
Hope this helps! ;)
Speed is constant. 50 miles = 1 hour. 600/50 = 12. 1hr(12) = 12 hours.
