The Change In Gravitational Potential Energy?

Click For Summary
SUMMARY

The discussion centers on calculating the work done by gravitational force and the change in gravitational potential energy for a 2.40 kg snowball fired from a 10.4 m high cliff with an initial velocity of 19.3 m/s at an angle of 42.0° above the horizontal. The work done on the snowball by gravity is determined to be 245 Joules, while the change in gravitational potential energy is calculated as -245 Joules when considering the potential energy at the height of the cliff as zero. The problem is sourced from Halliday's "The Fundamentals of Physics," 8th edition, specifically problem 6 from chapter 8.

PREREQUISITES
  • Understanding of gravitational potential energy (GPE) and its formula: GPE = mgh
  • Familiarity with the concept of work done by conservative forces
  • Knowledge of vector components in projectile motion
  • Basic proficiency in algebra and trigonometry for solving physics problems
NEXT STEPS
  • Review the concept of conservative forces and their implications in physics
  • Study the derivation and application of the work-energy theorem
  • Learn about projectile motion and how to resolve vectors into components
  • Explore additional problems in Halliday's "The Fundamentals of Physics" for practice
USEFUL FOR

This discussion is beneficial for physics students, educators, and anyone interested in understanding the principles of gravitational potential energy and work done by forces in classical mechanics.

Scray XXI
Messages
2
Reaction score
0

Homework Statement


A 2.40 kg snowball is fired from a cliff 10.4 m high. The snowball's initial velocity is 19.3 m/s, directed 42.0° 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 cliff, what is its value when the snowball reaches the ground?

Homework Equations


Gravitational Potential Energy = mgh
or = (mgd)cos(theta)

The Attempt at a Solution


I have concluded that the answers to parts a) and c) are both positive and negative 245 Joules respectively. I am just having a little trouble with part b). I used the (mgd)cos(theta) equation and I also attemped to change its sign and both times I was wrong. This is problem 6, chapter 8 of Halliday's The Fundamentals Of Physics 8th edition.
 
Physics news on Phys.org
Bump for despirately not knowing how to solve a problem...
 
The gravitational force is conservative. The work done by it depends only on initial and final positions of the object.. That should help you a lot.
 
K + U = K_o + U_o
 

Similar threads

Gravitational Potential Energy Problem
  • · Replies 4 ·
Replies
4
Views
3K
Misunderstanding of Gravitational Potential Energy
  • · Replies 7 ·
Replies
7
Views
3K
Gravitational Potential Energy questions near the surface of a planet
  • · Replies 8 ·
Replies
8
Views
2K
Help finding the change in potential energy in this problem
  • · Replies 9 ·
Replies
9
Views
933
Challenging problem about an impact with a smooth frictionless surface
  • · Replies 55 ·
2
Replies
55
Views
5K
Is the line integral of tangential force in pendulum equal to the negative of change in potential energy?
  • · Replies 3 ·
Replies
3
Views
1K
Deriving gravitational potential energy -- mistake
  • · Replies 9 ·
Replies
9
Views
2K
Potential energy of ball thrown upwards
  • · Replies 5 ·
Replies
5
Views
14K
Calculating Gravitational Potential
  • · Replies 3 ·
Replies
3
Views
1K
Elliptical orbit/ determine speed & potential energy
  • · Replies 1 ·
Replies
1
Views
1K