How many joules of potential energy does a 1-kg book gain when it is elevated 4 m? When it is elevated 8 m?

1 Answer
Apr 12, 2017

#color(blue)("potential energy") = kg xx "9.8m/s"^2xx h#

Where kg is the weight of the object in kg
his height in meters

9.8m/#s^2# is the acceleration due to gravity (9.8 m / s2 at the surface of the earth)

The formula for calculating the potential energy of a spring is different . This only applies for gravitational force.

Plug in the variables

#1kg xx "9.8m/s"^2xx4m =39.2kg * m^2"/"s^2#

#1kg * m^2"/"s^2 =1J#

Thus the potential energy is 39.2J

#1kg xx "9.8m/s"^2xx8m = 78.4kg * m^2"/"s^2#

So the potential energy increases with the height because the gravitational force is weaker at more height.The same is for magnetic force.If place an iron bar above the magnet ,the more nearer the iron or it can be said that at a low height from the magnet the force is stronger than the force of a magnet when an iron bar is at high heights.