The concepts in this problem are similar to those inMultiple-Concept Example 4,

Question

The concepts in this problem are similar to those inMultiple-Concept Example 4, except that the force doing the work inthis problem is the tension in the cable. A rescue helicopter liftsa 90.2-kg person straight up by means of a cable. The person has anupward acceleration of 0.671 m/s2 and is lifted fromrest through a distance of 8.18 m. (a) What is thetension in the cable? How much work is done by (b)the tension in the cable and (c) the person'sweight? (d) Use the work-energy theorem and findthe final speed of the person.

Explanation / Answer

A rescue helicopter lifts a 90.2-kg person straight up by means ofa cable. The person has an upward acceleration of 0.671m/s2 and is lifted from rest through a distance of 8.18m. (a) What is the tension in the cable? How muchwork is done by (b) the tension in the cable and(c) the person's weight? (d) Usethe work-energy theorem and find the final speed of the person. (a) a = .671 m/s^2 the net force is T - mg = ma T = m(g+a) = 90.2(9.8+.671) = 944.5 N (b) work done by T = T(displacement) = 944.5*8.18 = 7725.9 J (c) work done by weight = -(90.2)(9.8)(8.18) = -7230.8 J (d) net work done = change in KE 7725.9-7230.8 = (1/2)(90.2)v^2 v = (2(7725.9-7230.8)/90.2) = 3.31 m/s

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.