Question

A 1.85 kg textbook is sitting on a bookshelf 2.23 m above the floor. How much potential energy does it have?

Answer 1

Answer:

$\boxed {\boxed {\sf 40.4299 \ Joules}}$

Explanation:

Potential energy is energy due to position. It is the product of mass, height, and acceleration due to gravity.

$PE= m \times g \times h$

The mass of the textbook is 1.85 kilograms. Assuming this is on Earth, the acceleration due to gravity is 9.8 meters per square second. The height is 2.23 meters.

• m= 1.85 kg
• g= 9.8 m/s²
• h= 2.23 m

Substitute the values into the formula.

$PE = 1.85 \ kg \times 9.8 \ m/s^2 \times 2.23 \ m$

Multiply the first 2 numbers together.

$PE=18.13 \ kg*m/s^2 *2.23 \ m$

Multiply again.

$PE= 40.4299 \ kg*m^2/s^2$

• 1 kilogram square meter per square second (1 kg*m²/s²) is equal to 1 Joules (J)
• Our answer of 40.4299 kg*m²/s² is equal to 40.4299 J

$PE= 40.4299 \ J$

The textbook has 40.4299 Joules of potential energy.