Mass= density x volume
1.3 kg/m^3 x ( 2.5x4x10) m^3
= 130 kg
<h3><u>Answer</u>;</h3>
1600 years
<h3><u>Explanation</u>;</h3>
- Half life is the time taken for a radioactive isotope to decay by half of its original amount.
- We can use the formula; N = O × (1/2)^n ; where N is the new mass, O is the original amount and n is the number of half lives.
- A sample of radium-226 takes 3200 years to decay to 1/4 of its original amount.
Therefore;
<em>1/4 = 1 × (1/2)^n</em>
<em>1/4 = (1/2)^n </em>
<em>n = 2 </em>
Thus; <em>3200 years is equivalent to 2 half lives.</em>
<em>Hence, the half life of radium-226 is 1600 years</em>
Physics- damon, Monday, December 1, 2014 at 3:27 pm force =change in momentum\ change in time or m a if m is constant
change in momentum/3=200
change in momentum =3*200 kg m/s
Answer:
k = 40 N/m
Explanation:
A spring's energy is given:
U is the energy in the spring, k is the spring constant and x is the spring displacement.
We are told that the spring stores 5J of energy, therefore, U = 5J. We are also told that the spring is compressed by 0.5m, so the spring x = 0.5m
k = 40 N/m
Hope this helps!
