Only 4 questions plz answer.

Abearing is designed to a reduce friction b. support a load c.guide moving parts such as wheels, shafts and pivots d. all of the above

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

Suppose a comet has an orbital period of 309.1 years around the sun. what is it’s average distance from the sun?