A particle of mass m is acted upon by a force F given by the empirical law F = Rt²v(t). If this law is to be tested experimentally by observing the motion starting from rest, the best way is to plot:

F = Rt²v(t) ⇒ mdv/dt = Rt²v(t)
⇒ dv/v = (R/m)t²dt
Integrating both sides,
∫dv/v = (R/m)∫t²dt
lnv = (R/m)(t³/3) + c
Since the motion starts from rest, at t=0, v=0. Therefore, c = 0.
lnv = (R/3m)t³
Taking antilogarithm on both sides,
v = exp[(R/3m)t³]
Taking logarithm on both sides,
logv = (R/3m)t³
Plotting logv against t³ will give a straight line with slope (R/3m).