NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part. == The acceleration of a particle is defined by the relation a = -kv, where k is a constant. Know that x = 0 and v=81 m/s at t=0 and that v= 40 m/s when x = 26 m. Determine the time required for the particle to come to rest. The time required for the particle to come to rest is S.