Classify which of the following is a substance: tablero salt, seawater or sand? explain how you know.

1. a net force of 100 newton’s is applied to a wagon for 5 seconds. this causes the wagon to undergo a change in momentum of

In a stagnant pool of water, a crayfish may spend much of its time lying with one side of its carapace near the surface of the water. in this position, it will move the walking legs on that side in a rhythmic back-and-forth motion. explain the likely function of this behavior.

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