Kinetic energy of a moving projectile (8317)

, por F_y_Q

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Calculate the kinetic energy of an 18 g projectile moving horizontally at 97\ m\cdot s^{-1}.

P.-S.

If you observe the units in the problem statement, you will see that the mass is not expressed in the SI unit of mass. The first thing you need to do is convert it to kg to make the problem homogeneous.

18\ \cancel{g}\cdot \frac{1\ kg}{10^3\ \cancel{g}} = \color[RGB]{0,112,192}{\bf 0.018\ kg}

The kinetic energy of the projectile is given by the equation:

\color[RGB]{2,112,20}{\bm{E_C= \frac{m}{2}\cdot v^2}}

You know the necessary data, so you just need to substitute and calculate:

E_C = \frac{0.018\ kg}{2}\cdot 97^2\ m^2\cdot s^{-2} = \fbox{\color[RGB]{192,0,0}{\bf 84.7\ J}}