Answer:
Yes.
The nuclear equation {226/88 Ra → 222/26 Rn + 4/2 He} is balanced. As we know that an alpha particle is identical to a helium atom. This implies that if an alpha particle is eliminated from an atom's nucleus, an atomic number of 2 and a mass number of 4 is lost.
Therefore, the equation will be reduced to:
226 - 4 = 222
88 - 2 = 86
Hence, the equation is balanced.
Explanation:
Average speed is total distance divided by total time.
Total distance is 50 m + 150 m + 300 m = 500 m
Total time is 68 s + 35 s + 22 s = 125 s
Average speed is 500 m / 125 s = 4 m/s
Answer: balanced chemical equation: 
Net ionic equation :
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
The balanced chemical equation is:

Spectator ions are defined as the ions which does not get involved in a chemical equation or they are ions which are found on both the sides of the chemical reaction present in ionic form.
The ions which are present on both the sides of the equation are sodium and nitrate ions and hence are not involved in net ionic equation.
Hence, the net ionic equation is
Answer:
19.6 J
Step-by-step explanation:
Before the ball is dropped, it has a <em>potential energy
</em>
PE = mgh
PE = 0.2 × 10 × 9.8
PE = 19.6 J
Just before the ball hits the ground, the potential energy has been converted into kinetic (<em>mechanical</em>) energy.
KE = 19.6 J