A 3.4 kg object is lifted from the floor and placed on a shelf that is 2.3 m above the floor. What is the gravitational potential energy of the object sitting on the shelf?

Group of answer choices

7.9 J

0.2 J

14.5 J

76.6 J

1 answer

The gravitational potential energy (GPE) of an object can be calculated using the formula:

\[ \text{GPE} = m \cdot g \cdot h \]

Where:

  • \( m \) is the mass of the object (in kilograms),
  • \( g \) is the acceleration due to gravity (approximately \( 9.81 , \text{m/s}^2 \)),
  • \( h \) is the height above the reference point (in meters).

For the given object:

  • Mass \( m = 3.4 , \text{kg} \)
  • Height \( h = 2.3 , \text{m} \)
  • Acceleration due to gravity \( g \approx 9.81 , \text{m/s}^2 \)

Now, substituting the values into the formula:

\[ \text{GPE} = 3.4 , \text{kg} \cdot 9.81 , \text{m/s}^2 \cdot 2.3 , \text{m} \]

Calculating this step-by-step:

  1. Calculate \( 3.4 \times 9.81 \):

\[ 3.4 \times 9.81 \approx 33.434 \]

  1. Now multiply by the height \( 2.3 \):

\[ 33.434 \times 2.3 \approx 76.9 , \text{J} \]

Therefore, the gravitational potential energy of the object sitting on the shelf is approximately \( 76.9 , \text{J} \).

Among the options given, the closest value is:

76.6 J