What is velocity and how do you calculate it?

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

Identify the theory that can be used to explain each phenomenon. answers diffraction: wave theory interference: wave theory reflection: both particle and wave theories refraction: both particle and wave theories

Marcella is a four-year-old girl who is a victim of emotional child abuse. based on the child and family services improvement and innovation act of 2011, which action should the government take for marcella? a. the state should arrest marcella’s abuser. b. the state should find a home for marcella as soon as possible. c. the state should enforce stricter laws in the area where marcella resides. d. the state should provide medical assistance to marcella.