Question

If an object moving at 12 m/s has a kinetic energy of 72 j what is the mass

Answer 1

Simply, apply the formula $E = \frac{1}{2}mv^{2}$ and insert the values of m = mass, v = velocity and E = Energy.
The result will be $72J = \frac{1}{2}m(12m/s)^{2}$, m = 1 kg