Jumping on the force plate you can feel the force. We use time of flight method to estimate the height of the jump.
s = s 0 + v 0 t + 1 2 a t 2 {\displaystyle s=s_{0}+v_{0}t+{\tfrac {1}{2}}at^{2}} and thus we have h = v 0 t − 1 2 g t 2 {\displaystyle h=v_{0}t-{\tfrac {1}{2}}gt^{2}} because h 0 = 0 {\displaystyle h_{0}=0} and a = − g = − 9.81 m / s 2 {\displaystyle a=-g=-9.81m/s^{2}} . However, for the velocity we have v = v 0 − g t {\displaystyle v=v_{0}-gt} and at the maximum height we have that v = 0 {\displaystyle v=0} , and thus v 0 = g t m {\displaystyle v_{0}=gt_{m}} . Combining these two we have
h = v 0 t − 1 2 g t 2 = g t m 2 − 1 2 g t m 2 = 1 2 g t m 2 {\displaystyle {\begin{matrix}h&=v_{0}t-{\tfrac {1}{2}}gt^{2}\\&=gt_{m}^{2}-{\tfrac {1}{2}}gt_{m}^{2}\\&={\tfrac {1}{2}}gt_{m}^{2}\end{matrix}}}
The time at the maximum height ( t m {\displaystyle t_{m}} ) will be half of the flight time.
In the experiment, we have t m = 0.16 {\displaystyle t_{m}=0.16} s, which gives h = 1 2 g t m 2 = 1 2 × 9.81 × 0.16 2 = 0.13 {\displaystyle h={\tfrac {1}{2}}gt_{m}^{2}={\frac {1}{2}}\times 9.81\times 0.16^{2}=0.13} m.