We are given the initial speed and kinetic energy, so we can solve for the mass:
$14 J = \frac{1}{2}m(3.5 m/s)^2$
Now, we can solve for m:
$m = \frac{2 \times 14 J}{(3.5 m/s)^2} = \frac{28 J}{12.25 (m^2/s^2)} = 2.29 kg$
So, the mass of the object is 2.29
Show more…