$6\mathrm{.}4.$ A machine punching $38mm$ holes in $32mm$ thick plate requires $700KN*m$ of energy per square $cm$

of sheared area, and punches one hole in every $10$ seconds. Calculate the power of the motor required.

The mean speed of the flywheel rim is $25\frac{m}{sec}.$ Find the mass of the flywheel required if the total

fluctuation of speed is not to exceed $3\%$ of the mean speed. Assume that the motor supplies energy to

the machine at a uniform rate and the punching process takes $1\mathrm{.}6$ second and requires energy at a

uniform rate.