An object of mass weighing 5.24 kilograms is raised to a height of 1.63 meters. What is the potential energy of the object at that height? Note that acceleration due to gravity is 9.8 meters/second2. A. 65 joules B. 84 joules C. 91 joules D. 1.0 × 102 joules E. 1.5 × 102 joules



Answer :

AL2006

"Kilogram" is not a unit of force, and no object "weighs" 5.24 kilograms.

The weight of an object is

             (its mass) x (the acceleration of gravity where the object is) .

Notice that the object's weight depends on gravity in the place where
the object is, so the same object ... with the same mass ... has different
weights in different places. 

On Earth, the acceleration due to gravity is about

                                     9.8 meters per second-squared,

so the object's weight is about

                     (5.24 kilograms) x (9.8 m/s²)  =  51.352 Newtons .

But that's not what this question is asking.  I just needed to straighten
out that part where you said that the object 'weighs' 5.24 kilograms.

========================================

An object's gravitational potential energy is

             (mass) x (gravity) x (height)  = 

    (5.24 kilograms) x (9.8 m/s²) x (1.63 meters)  = 

           83.7  kilogram-meter² / second²  =  83.7 joules .

           Choice 'A' is this number, rounded to the nearest integer.


Answer:

B.  84 joules

Explanation:

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