Gravitational Potential Energy

Click For Summary
SUMMARY

The discussion centers on Gravitational Potential Energy and the forces involved in lifting objects. It clarifies that to lift an object at a steady speed, the applied force must equal the object's weight, counteracting gravity. Examples such as riding an escalator illustrate this principle, where the escalator exerts an upward force equal to the weight of the person. The conversation also highlights the impact of friction and the need for excess force to initiate movement or overcome resistance.

PREREQUISITES
  • Understanding of Newton's laws of motion
  • Basic knowledge of forces and weight
  • Familiarity with concepts of friction and stiction
  • Grasp of Gravitational Potential Energy principles
NEXT STEPS
  • Study Newton's laws of motion in detail
  • Explore the concept of Gravitational Potential Energy in various contexts
  • Investigate the effects of friction on motion and energy transfer
  • Learn about the relationship between force, mass, and acceleration
USEFUL FOR

Students of physics, educators teaching mechanics, and anyone interested in understanding the principles of forces and energy in motion.

averycasille
Gold Member
Messages
9
Reaction score
0
Hello, I do not quite get this. Can anyone provide examples?
" We may feel that it takes a force greater than the weight of the object being raised to lift it upwards, but it is not so. Provided the force is equal to the weight, the object will move upwards at a steady speed. "
 
Physics news on Phys.org
averycasille said:
Hello, I do not quite get this. Can anyone provide examples?
" We may feel that it takes a force greater than the weight of the object being raised to lift it upwards, but it is not so. Provided the force is equal to the weight, the object will move upwards at a steady speed. "
If you are riding an escalator upward, you feel the ordinary force of gravity. Your feet push down on the escalator with your normal weight and the escalator supports you by exerting an equal and opposite upward force.

Of course, when you step onto the escalator there must be a momentary increased upward push and when you step off, there must be a momentary decreased upward push.
 
  • Like
Likes   Reactions: DrewD
averycasille said:
Hello, I do not quite get this. Can anyone provide examples?
" We may feel that it takes a force greater than the weight of the object being raised to lift it upwards, but it is not so. Provided the force is equal to the weight, the object will move upwards at a steady speed. "
I agree that this is not totally intuitive. I think that your problem is because in any practical situation there is friction (and stiction), which will 'naturally' slow things down and would require some small excess of upward force over the weight for the mass to keep rising. Plus, to accelerate the object in the first place, will require an excess force. Before Newton, people believed that everything naturally slows down, which was not totally unreasonable, in a world where even wheeled vehicles slowed down on the level, due to rubbish bearings and road surfaces. They believed that the Planets were being pushed around, for the same reason.
Also, you have to keep pushing (to compensate for the loss in Gravitational Potential Energy.
 

Similar threads

High School Conceptually understanding change in potential energy with 0 net work
  • · Replies 9 ·
Replies
9
Views
2K
High School Potential energy and lifting an object vertically
  • · Replies 29 ·
Replies
29
Views
4K
High School How does an object gain potential energy?
  • · Replies 54 ·
2
Replies
54
Views
6K
Undergrad Gravitational potential energy
  • · Replies 46 ·
2
Replies
46
Views
5K
Graduate Gravitational potential energy -- Why is it always negative?
  • · Replies 10 ·
Replies
10
Views
3K
High School Can energy be decomposed?
  • · Replies 2 ·
Replies
2
Views
1K
Undergrad How does gravitational potential energy work?
  • · Replies 27 ·
Replies
27
Views
12K
Undergrad System, potential energy, and nonconservative forces
  • · Replies 6 ·
Replies
6
Views
2K
Undergrad How to relate the gravitational potential energy zero to the axes?
  • · Replies 4 ·
Replies
4
Views
3K
Undergrad What is the zero point for Potential Energy and how to find it from integral limits?
  • · Replies 6 ·
Replies
6
Views
2K