In an alpha decay, the original nucleus decays into a daughter nucleus + an alpha particle, which consists of 2 protons and 2 neutrons.
The atomic number (number of protons) of the Francium is 87, and since in the decay it loses 2 protons, the atomic number of the daughter nucleus should be 85. Looking at the periodic table ,this corresponds to Astatine, and therefore this is the element produced in the alpha decay of Francium-221.
Moreover, the mass number (number of protons+neutrons) decreases by 4 (because an alpha particle carries 2 protons+2 neutrons), therefore in the reaction the mass number will decrease from 221 to 217.
So, the daughter element is astatine-217.
Answer:
A - overloading the muscles too often
Explanation:
I Got It Right On Edge :)
Kinetic energy because the ball is in motion or moving with energy behind it... kinda like when you shoot a gun, the bullet is fired out of the muzzle with kinetic energy ( Punch ) and the bullet goes through a wall or something. Sorry but my math skills aren't very good to give complex calculations but I would recommend that you maybe talk to some of the top ranking math guys on the website. Maybe they can give you better help...
Anyways, I hope I have been helpful to you.
Answer:
its due to less surface area of action
pressure is high
Answer:
H = 171.90 m
Explanation:
given data
distance = 53.2 m
height = H
to find out
height H
solution
we know height is here H = 
......................1
here t is time and a is acceleration
so
we find t first
we know during time (t -1) s , it fall distance (H - 53.2) m
so equation of distance
................2
now subtract equation 2 from equation 1 so we get
53.2 = gt - 
53.2 = 9.81 t - 
t = 5.92 s
so from equation 1
H = 
H = 171.90 m
