Final answer:
The correct statements regarding a crane weighing 12,000 lbf are that it exerts a force of 12,000 pounds due to gravity and it weighs 12,000 pounds. The statements about experiencing a net force and having a mass of 12,000 pounds are not accurate without additional context.
Step-by-step explanation:
To determine what a construction crane weighing 12,000 lbf does:(a) Exerts a force of 12,000 pounds: Yes, the crane exerts a force due to gravity equal to 12,000 lbf, which is its weight. The unit pounds-force (lbf) implies the force due to gravity on an object.(b) Experiences a net force of 12,000 pounds: This would depend on whether the crane is in equilibrium or in motion. If the crane is stationary and not accelerating, then it does not experience a net force; the forces are balanced.
(c) Weighs 12,000 pounds: Absolutely correct, as weight is measured in pounds, and in this case, it is given as 12,000 lbf.(d) Has a mass of 12,000 pounds: This is incorrect. Mass would be measured in slugs in the imperial system or kilograms in the metric system. Mass and weight are different; weight is a force, and it is mass multiplied by the acceleration due to gravity.
Therefore, the correct options are (a) and (c), as they correctly describe the force exerted by the crane and its weight, respectively.