This is a combination reaction because two molecules becomes one
A + B ---> AB
The answer is 40.
We can solve this by finding out the number of protons, and neutrons. Atomic number of an element means the number of protons in that element. So, the atom has 30 protons if the atomic number is 30.
On the other hand, mass number is the total number of protons and neutrons, but not electrons, because they're too light comparing to the other 2. Therefore, we can simply solve the number of neutrons in the atom by subtracting the number of protons from the mass number. 70 - 30 = 40.
Therfore, the number of neutrons is 40.
Answer:
<h3>The answer is option D</h3>
Explanation:
To find the speed given the kinetic energy and mass we use the formula

where
m is the mass
v is the speed
From the question
KE = 15 J
m = 2.3 kg
We have

We have the final answer as
<h3>3.6 m/s</h3>
Hope this helps you