Gravitational energy potential

If height is measured in meters (m), potential energy is expressed in units of joules. Note that the weight (W) of the object is equal to the product mg, so we could also write that PE = Wlh. 

Together, kinetic and gravitational potential energy are referred to as mechanical energy. 

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AV is the net change in gravitational potential energy. This term is path independent and depends only on the initial and final heights, h and hj, above some arbitrary reference height with respect to the surface of the earth. 

A body of mass m at a height b above the surface of the Earth has a gravitational potential energy... 

EXAMPLE A.4 Sample exercise Calculating the gravitational potential energy... 

Self-Test A.5A What is the gravitational potential energy of this book (mass 1.5 kg) when it is on a table of height 0.82 m relative to its potential energy when it is on the... 

I 4 Calculate the gravitational potential energy of an object (Example A.3). 

Removing an electron from a nucleus increases the electrical potential energy. Lifting a backpack from the floor to a tabletop increases the gravitational potential energy. 

C06-0008. Which of the following are state functions (a) height of a mountain (b) distance traveled in climbing that mountain (c) energy consumed in climbing the mountain and (d) gravitational potential energy of a climber on top of the mountain... 

The quantum levels of an electron bound to an atom are cmdely analogous to the gravitational potential energies available to a ball on a staircase. As illustrated in Figure 7-12. a ball may sit on any of the steps. If we define the top of the steps to be 5" = 0, the ball has a negative potential energy when it is on any of the lower steps. To move a ball from the bottom of the staircase to step 5 requires the addition of a specific amount of energy,... 

Gravitational potential energy (associated with the attraction between separated masses)... 

In the absence of nuclear energy sources, a star contracts on a thermal timescale and radiates energy at the expense of gravitational potential energy. Since, by the Virial Theorem, the total energy... 

Figure 2.37. A simple mechanical system and its equilibrium states. Different positions of a block on a stand and the corresponding values of the gravitation potential energy are shown. Point G is the centre of gravity of the block. In A there is stable equilibrium, in C metastable, in B unstable.

Position C does not correspond to the lowest minimum of the energy following a small displacement, the block will return to the initial position whereas large displacements will move the block to the more stable position A. In A there is an (absolutely) stable equilibrium and in C a metastable equilibrium. For this mechanical system the stability conditions and the trends of spontaneous (natural) processes are related to minima (relative or absolute) of the gravitational potential energy. 

The critical density is traditionally dehned as that density which separates the closed (finite) universe from the open (infinite) universe in the simplest model available, i.e. in a universe without cosmological constant or quintessence. It corresponds to a universe with zero total energy, where the kinetic energy due to expansion is exactly balanced by gravitational potential energy. The value of the critical density is 10 gcm, which amounts to very httle when compared to a chunk of iron ... 

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