Please solve last four questions

If vx = 7.00 units and vy = -7.60 units, determine the magnitude of v⃗ . determine the direction of v⃗ .

Examine the nuclear reacti why is this classified as a nuclear reaction rather than a chemical reaction? it is not balanced. a new compound is formed. a change has occurred in a nucleus. a new element has been formed.

Find the magnetic field a distance r from the center of a long wire that has radius a and carries a uniform current per unit area j in the positive z direction.