A5.50 kg object initially at rest at the origin is subjected to the time-varying force shown in the figure. what is the object's velocity at t=6s?

Refer to the figure shown below.

m = 5.50 kg, the mass of the object

The force is modeled by the piecewise function
F(t) = 2.5t N, 0 ≤ t ≤ 4 s
      = 0,         4 < t ≤ 6 s

The acceleration due to the piecewise force is
a(t) = F(t)/m

That is,
a(t) = 2.5t/5.5 m/s², 0 ≤ t ≤4 s
      = 0,                   4 < t ≤ 6 s

The velocity at  t = 6 s is


A graph of velocity versus time is shown.

3.636 m/s