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Lesson 2: Energy

# Gravitational potential energy derivation

Let's derive expression for gravitational potential energy.  Created by Mahesh Shenoy.

## Want to join the conversation?

• I don't understand please annunciate.
• in the example of the pendulum, what force is doing the work??
the least i can make out is that it isnt gravitational force that is doing the work of making the pendulum move because the acceleration or displacement of the pendulum is sideways
and not downward, am i correct and someone please answer my question
(1 vote)
• It is the gravitational force only which does the work.

I appreciate your assumption that it must not be gravitational force as the motion here is sidewards. However, the downward pull exerted by the gravitation here acts sidewards as the pendulum is connected to a rigid end and can't come downwards.

What I say maybe doesn't make absolute sense, because the rigorous explanation of your question requires the mathematical understanding of vectors and vector components, which you will learn in the Class 11 physics course

Hope that helped. Feel free to comment if you need further help :)
(1 vote)
• I think that she means the higher an object is,the more gravitational potential energy it has.
(1 vote)
• wont the actual P.E. be 55.8?
60 is way off...
(1 vote)
• Hey! If the value of g is calculated with the distance taken from the center of the earth, shouldn't the height be considered from the center of the earth too?
(1 vote)
• why would the displacement in the pendulum be taken as the highest point and lowest point, clearly it has had much more spatial displacement. so the net force is going to be in the direction of the displacement aka around the hypotenuse of that 'h' isnt it?
(1 vote)