You and three friends stand at the corners of a square whose sides are 8.0 m long in the middle of the gym floor, as
shown in the figure. You take your physics book and push it from one person to the other. The book has a mass of
1.7 kg, and the coefficient of kinetic friction between the book and the floor is µk = 0.30.
1. The book slides from you to Beth and then from Beth to Carlos, along the lines connecting these people. What
is the work done by friction during this displacement?
2. You slide the book from you to Carlos along the diagonal of the square. What is the work done by friction
during this displacement?
3. You slide the book to Kim who then slides it back to you. What is the total work done by friction during this
motion of the book?
4. Is the friction force on the book conservative or nonconservative?
The picture is very simple its a square with side lengths of 8 m. Starting from the top left hand corner going clockwise: Beth, Carlos, Kim , You in the corners
Physics help?
2016-03-05 1:25 am
回答 (2)
2016-03-05 1:44 pm
✔ 最佳答案
At all times, the friction force isF = µmg = 0.30 * 1.7kg * 9.8m/s² = 5.0 N
The side lengths are 8.0 m, so the diagonal lengths are 8.0m*·2 = 11.3 m.
You and Carlos are a diagonal length apart.
1. Wf = F*d = 5.0N * 2 * 8.0m = 80 J
and you may need a negative sign since the direction of the force is opposed to the direction of motion.
2. Wf = 5.0N * 11.3m = 57 J
and again, you may need a negative sign.
3. Wf = 5.0N * 2 * 8.0m = 80 J
and...
4. Since the work done is path dependent (or since you can't "recover" your work by retracing the path), the force is non-conservative.
Hope this helps!
參考: Revisit this please:
https://answers.yahoo.com/question/index?qid=20160219152456AAxTbbB
TIA
2016-03-05 1:30 am
Someone will help you soon
收錄日期: 2021-04-21 17:11:38
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160304172558AAxUoGF