Question

Please help me understand with steps, I really don't get it

A square plate has a side length of 1.20 m. A 24.0-N ~ m torque is applied about an axis perpendicular to the plate through its center. If it experiences an angular acceleration of 6.25 rad/s2, calculate the mass of the plate.

Answer 1

https://www.chegg.com/homework-help/moment-inertia-square-plate-mass-m-length-l-rotates-axis-per-chapter-8-problem-49p-solution-9781111021092-exc
==========================================
I = (1/6) m L^2

Torque = I * angular acceleration
24 = (1/6) m L^2 * 6.25^2
but L = 1.2
so
24 = (1/6) m (1.2*6.25)^2