WOE - Potential Energy

Potential Energy

Potential energy is energy that is stored due to the position of some object. Gravitational potential energy is due to the position of an object in relation to the gravitational force that is being applied to it. For practical purposes this means due to the height of the object from some arbitrary zero point. The spring potential energy is due to the position of the spring and how much it has been displaced from its equilibrium position. The spring potential energy depends on the amount of displacement and the spring constant of the spring. Hooke's law states that a force applied to a spring will cause a displacement proportional to the force applied. Please watch the following presentation that will discuss gravitational potential energy and spring potential energy. 

Potential Energy Practice

Gravitational and spring potential energy both are related to the work done on the objects for them to reach their present state. Please watch the following presentation of some example problems.

Potential Energy Self-Assessment

Now it is your turn. Complete the following Potential Energy problems to verify that you understand how to apply the equations for gravitational and spring potential energy.

  1. A little boy of mass 25 kg is swinging on his swing in the back yard.   The swing is 3 m long and swings to a maximum angle of 50o to the horizontal.  At the bottom of the swing, the boy's center of mass is 0.6 m above the ground. Calculate the potential energy of the boy with respect to the ground when he is
    1. At his highest point. 
    2. At his lowest point. 

SOLUTIONS Links to an external site.

  1. A spring with a coefficient of 350 N/m is compressed 7 cm between a wall and a 7.5kg mass.  
    1. What is the force exerted by the spring on the box? 
    2. How much energy is stored on in the compressed spring? S
    3. If the coefficient of friction between the box and the surface is 0.15, what will be the acceleration of the box at the moment the spring is released? 

SOLUTIONS Links to an external site.

Potential Energy Practice Problems

Download Potential Energy Practice Problems Links to an external site. for more practice. 

Download solutions Links to an external site. to the practice problems. 

VIDEOS CREATED BY GAVS

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