If an atom has two electrons outside of its nucleus, what number of protons and neutrons must be contained in the nucleus to result in a neutral atom

2 protons and 2 neutrons.

Explanation: this means that it contains 2 negatively charged elections and 2 positively charged protons which cancels each other to make the atom electrically neutral.

i think it because equal matrices have equal dimensions, only square matrices can be symmetric. for all indices and . every square diagonal matrix is symmetric, since all off-diagonal elements are zero. in linear algebra, a real symmetric matrix represents a self-adjoint operator over a real inner product space.

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be