A 20.0kg child plays on a swing having support ropes that are 1.80m long. A frie

Question

A 20.0kg child plays on a swing having support ropes that are 1.80m long. A friend pulls her back until the ropes are 39.0? from the vertical and releases her from rest.

A.What is the potential energy for the child just as she is released, compared with the potential energy at the bottom of the swing?

B.How fast will she be moving at the bottom of the swing.

C. How much work does the tension in the ropes do as the child swings from the initial position to the bottom?

Please show answers as well as Equations

Explanation / Answer

a) PE = mgh

h is the vertical difference of when the swing is at rest (1.8 m) and when the child is pulled back.

Find the height when the child is pulled back:
cos 39 = y/1.8
y = 1.8 cos 39 = 1.39 m

Therefore, the difference (1.8 m - 1.39 m = .41 m) is h
PE = (20 kg)(9.8 m/s

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

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