The figure is a graph of the force exerted by the floor on a woman making a vertical jump?

perhaps the question is:

at what speed does she leave the ground? Hint: The force of the floor is not the only force acting on the woman.

from the graph at t =0, the floor exerts an upward force on the lady = to her weight = 600 N = mg

=> m = 600/g = 600 / 9.81 = 61.16 kg

F̂ₐᵥₑΔt = Î = Impulse = change in momentum = Δ(mv̂)

here Fₐᵥₑ(net)Δt = area of the graph with the x-axis – impulse due to her weight(downwards)

= 600(0.2) + ½(0.275)1800 + (0.275)600 + ½0.025(600) – 600(0.5)

= 240 N

therefore 240 = mΔv = 61.16 [v – 0]

=> v = 240/61.16 = 3.896 m/s

hope this helps