Answer: half life
Explanation: Radioactive decay follows first order kinetics and the time required for the decay of a radioactive material is calculated as follows:

t= time required
k= disintegration constant
x= amount of substance left after time t
a= initial amount of substance
when one half of the sample is decayed, one half of the sample remains and t can be represented as 
at
, 


Final velocity(v) = 32 m/s
Initial velocity(u) = 10 m/s
Using kinematic equation v = u + at,
32 = 10 + a(3)
32-10
--------- = a
3
a = 22
----
3
a = 7.3 m/s^2.
Hence acceleration of the roller coaster is 7.3 m/s^2.
Hope this helps!!
Answer:
when CO2 gas is passed through lime water it turns milky due to the formation of calcium carbonate which formula is CaCO3.
Ca(OH)2+ CO2------ CaCO3
when excess of carbon dioxide is passed through calcium carbonate calcium hydrogen carbonate is formed and solution become colourless.
CaCO3+CO2------ Ca(HCO3)
Scientists developed symbols and gave the elements numbers to help organize the elements by their chemical properties. The periodic table helps identify the underlying chemical and physical traits of the elements.