8. the acceleration of an object is zero. which best describes the possible motion of the object?

the object is traveling at constant velocity or is slowing down.

the object is traveling at constant speed but may be changing direction.

the object is at rest or is traveling at constant velocity.

the object is at rest.

Plss anybody know how to do this? ? i need the answers from a through d

In the sport of parasailing, a person is attached to a rope being pulled by a boat while hanging from a parachute-like sail. a rider is towed at a constant speed by a rope that is at an angle of 15 ∘ from horizontal. the tension in the rope is 1900 n. the force of the sail on the rider is 30∘ from horizontal. what is the weight of the rider? express your answer with the appropriate units.

30 points - when can a theory be modified if a new type of technology allows for new observations that raise new questions? a. immediately, while the questions about the theory are being asked b. after new hypotheses related to the theory are tested in experiments c. only after the new observations disprove all parts of the theory d. while scientists begin to think about how the theory could improve