Rutherford's experiment<span> utilized positively charged alpha particles (He with a +2 charge) which were deflected by the dense inner mass (nucleus). The conclusion that could be formed from this result was that </span>atoms<span> had an inner core which contained most of the mass of an </span>atom<span> and was positively charged.</span>
That would be a maximum of 4 atoms
Smaller cars have less momentum than bigger cars. What’s in motion stays in motion but objects with more momentum (can be from weight or from speed but in this case it’s about weight) tend to stay in motion longer.
Answer:
a) 
b) 

Explanation:
Searching the missed information we have:
E: is the energy emitted in the plutonium decay = 8.40x10⁻¹³ J
m(⁴He): is the mass of the helium nucleus = 6.68x10⁻²⁷ kg
m(²³⁵U): is the mass of the helium U-235 nucleus = 3.92x10⁻²⁵ kg
a) We can find the velocities of the two nuclei by conservation of linear momentum and kinetic energy:
Linear momentum:


Since the plutonium nucleus is originally at rest,
:
(1)
Kinetic Energy:

(2)
By entering equation (1) into (2) we have:
Solving the above equation for
we have:

And by entering that value into equation (1):
The minus sign means that the helium-4 nucleus is moving in the opposite direction to the uranium-235 nucleus.
b) Now, the kinetic energy of each nucleus is:
For He-4:

For U-235:

I hope it helps you!