A person is riding on a Ferris wheel of radius R. He starts at the lowest point

Question

A person is riding on a Ferris wheel of radius R. He starts at the lowest point of the wheel. When the wheel makes one complete revolution, is the net work done by the gravitational force positive, zero or negative? Do you need to know how the speed of the person changed before you can answer the question? b) Suppose the person started at the highest point of the wheel. What is the net work done by the gravitational force when he reaches the lowest point? A 50-kg block is pushed a distance of 5.0 m across a floor by a horizontal force F_P whose magnitude is 150 N. F_P is parallel to the displacement of the block. The coefficient of kinetic friction is 0.25. a) What is the total work done on the block? b) If the box started from rest, what is the final speed of the block?

Explanation / Answer

3.

a) Net work done by gravitational force = 0 as net displacement is equal to 0. No, there is no need of knowledge of the speed of the person or the change in speed of the person.

b) Net work done by gravitational force = mg(2R)

4.

a) total work done = work done by Fp + work done by kinetic friction

= Fp*5 - 0.25* mg * 5

= 150*5 - 0.25*50*10*5

= 750 - 625 = 125 J

b) Let final speed be v

(1/2) m v^2 = total work done= 125

v=(250/50)^0.5 = 2.236 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.