Chapter 08, Problem 008 A 2.10 kg snowball is fired from a cliff 8.55 m high. Th

Question

Chapter 08, Problem 008 A 2.10 kg snowball is fired from a cliff 8.55 m high. The snowball's initial velocity is 11.8 m/s, directed 39.0° above the horizontal. (a) How much work is done on the snowball by the gravitational force during its flight to the flat ground below the cliff? (b) What is the change in the gravitational potential energy of the snowball-Earth system during the flight? (c) If that gravitational potential energy is taken to be zero at the height of the dliff, what is its value when the snowball reaches the ground? (a) Number (b) Number (e) Number By this Assistance, you will learn while you earn points based on the Point Potential Policy set by your instructor

Explanation / Answer

Initial Velocity = 11.8 m/s at 39o above horizontal

Initial Vertical Velocity Component = 11.8* sin39 = 7.425 m/s

Initial Horizontal Velocity Component = 11.8*cos39 = 9.17 m/s

g = 9.81 m/s^2

t = time to reach max height = 7.425/9.81 = 0.75 s

max height above cliff = h = 1/2gt^2 = (0.5)(9.81)(0.75)^2 = 2.759 m

Total Vertical distance of snowball = 8.55 + 2.759 = 11.30 m

Mass of snowball = 2.10 kg

Weight of snowball = 2.10*(9.81) = 20.60 N

a)

Work done by weight of snowball = 20.60(11.30) = 232.97 J  

b)

Change in GPE of snowball-Earth system = 232.97 J  

c)

If ref level is at cliff the change in GPE = -8.55* (20.60) = - 176.138 J

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

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