Answer:
[tex]\boxed {\boxed {\sf 7.84 \ Joules}}[/tex]
Explanation:
The formula for potential energy is:
[tex]PE=m*g*h[/tex]
where m is the mass, g is the gravitational acceleration, and h is the height.
The mass of the book is 0.4 kilograms. The gravitational acceleration on Earth is 9.8 m/s². The height of the book is 2 meters.
[tex]m=0.4 \ kg \\g=9.8 \ m/s^2 \\h=2\ m[/tex]
Substitute the values into the formula.
[tex]PE=(0.4 \ kg)(9.8 \ m/s^2)(2 \ m)[/tex]
Multiply the first two numbers.
- 0.4 kg*9.8 m/s²= 3.92 kg*m/s²
- If we convert the units now, the problem will be much easier later on.
- 1 kg*m/s² is equal to 1 Newton. So, our answer of 3.92 kg*m/s² is equal to 3.92 N
[tex]PE=(3.92 \ N )(2 \ m)[/tex]
Multiply.
- 3.92 N* 2 m=7.84 N*m
- 1 Newton meter is equal to 1 Joule (this is why we converted the units).
- Our answer is equal to 7.84 Joules.
[tex]PE=7.84 \ J[/tex]
