Question

The data table below shows the distribution of the energies of a pendulum 0.60 s into its motion. What is the missing value?

Answer 1

The total energy (also called mechanical energy) is the sum of the kinetic energy and potential energy:
$TE = KE + PE$
For this pendulum, we see that at t=0.60 s the total energy is TE=0.918 J while the potential energy is 0.054 J, so the kinetic energy (the missing value in the table) is
$KE=TE-PE=0.918 J - 0.054 J =0.864 J$