<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>
Answer:

Explanation:
The rotation rate of the man is:



The resultant rotation rate of the system is computed from the Principle of Angular Momentum Conservation:
![(90\,kg)\cdot (5\,m)^{2}\cdot (0.16\,\frac{rad}{s} ) = [(90\,kg)\cdot (5\,m)^{2}+20000\,kg\cdot m^{2}]\cdot \omega](https://tex.z-dn.net/?f=%2890%5C%2Ckg%29%5Ccdot%20%285%5C%2Cm%29%5E%7B2%7D%5Ccdot%20%280.16%5C%2C%5Cfrac%7Brad%7D%7Bs%7D%20%29%20%3D%20%5B%2890%5C%2Ckg%29%5Ccdot%20%285%5C%2Cm%29%5E%7B2%7D%2B20000%5C%2Ckg%5Ccdot%20m%5E%7B2%7D%5D%5Ccdot%20%5Comega)
The final angular speed is:

The air pressure is most likely lower.
Answer:
Explanation:
Let h be the height .
initial velocity in first case u = 0
final velocity v = 6 m /s
acceleration due to gravity g = 9.8 m /s²
v² = u² + 2 g h
6² = 0 + 2 x 9.8 x h
h = 1.837 m .
For second case u = 3 m /s
v² = u² + 2 gh
= 3² + 2 x 1.837 x 9.8
= 9 + 36
= 45 m
v = 6.7 m /s
Answer:
0.03167 m
1.52 m
Explanation:
x = Compression of net
h = Height of jump
g = Acceleration due to gravity = 9.81 m/s²
The potential energy and the kinetic energy of the system is conserved

The spring constant of the net is 20130.76 N
From Hooke's Law

The net would strech 0.03167 m
If h = 35 m
From energy conservation

Solving the above equation we get

The compression of the net is 1.52 m