The force-time (F-t) graph of a 10 kg moving object is shown (trapezoidal pulse: F rises from 0 to 20 N during 0-5 s, stays at 20 N from 5 to 20 s, then drops to 0 from 20 to 25 s). What is the final speed of the object?

The impulse imparted to the object equals the area under the F-t graph, which equals the change in momentum: J = Δp = m Δv. The trapezoid has parallel sides of 15 s (top, from t=5 to t=20) and 25 s (bottom, from t=0 to t=25) and height 20 N. Area = (1/2)(15 + 25)(20) = (1/2)(40)(20) = 400 N·s. Hence Δv = J/m = 400/10 = 40 m/s. Since the question asks for final speed (assuming starting from rest as no initial info is given), v = 40 m/s.