Which of the following represents a system that is completely open

Given the position vector of the particle r(t)=(t+1)i+(t^2−1)j+2t k, find the particle's velocity and acceleration vectors at t=1

Determine the change in width a, height b, thickness t when a plate is subjected to the uniform distributed load and is made of material having modulus of elasticity e=230 gpa and poisson's ratio ν=1/3. given : a=400 mm and b= 300 mm also the uniformly distributed load in downward y direction of plate is 2 mn/m and in the positive x direction is 3 mn/m and t=20 mm

It is really hard for me right know