Potential Energy - Work Done etc

AI Thread Summary
The discussion revolves around solving physics problems involving potential energy and motion. The first scenario involves two children of different masses on a rope, with calculations needed for the distance one child moves upward after the other lets go. The second scenario features a particle at rest on a hemisphere that is displaced slightly, requiring an expression for its speed in terms of the hemisphere's radius and gravitational acceleration. Participants emphasize the importance of visualizing the problems through diagrams to better understand the forces and motions involved. Clear calculations and understanding of the concepts of potential energy and motion are crucial for solving these problems.
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Please help me to solve the following question... I am really stuck.

1. Two children of mass 40 kg and 50 kg are holding on to the ends of a rope which passes over a thick horizontal branch of a tree. The parts of the rope on either side of the branch are vertical and the heavier child is moving downwards. A model is to be used in which the children may be considered as particles, and in which the rope is light and inextensible and is moving freely in a smooth groove on the branch. when the heavier child is moving at 2 m s^-1, she let's go of the rope. Calculate the further upward distance moved by the other child before falling back to the ground.
The motion described began with both children stationary. Calcuylate the distance they traveled before one let go of the rope.

2. A particle is at rest at the apex A of a smooth fixed hemisphere whose base is horixontal. Thhe hemisphere has centre O and radius a. The particle is then displaced very slightly from rest and moves on the surface where angle AQP=θ the particle has speed v. Find an expression for v in terms of a, g and θ.

Many thanks in advance!
 
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What are you stuck on?

You have a system with masses and forces acting on them. Have you drawn a diagram?
 
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