An 8.0-kg history textbook is placed on a 1.25-m high desk. How large is the gravitational potential energy of the textbook-earth system relative to the desktop?
98 J
8.0 x 9.8 x 1.25
98 j
relative to the floor it is m g h but relative to the desktop it is zero. You can do no work moving it down to the desk top if it is already on the desk top.
gravitational potential energy (J) = mass(kg) . gravity (N/kg) . height (m),
GPE = mgh 98J
980 J
To find the gravitational potential energy of the textbook-Earth system relative to the desk, we need to use the formula:
Gravitational Potential Energy = mass * acceleration due to gravity * height
Given:
Mass of the textbook (m) = 8.0 kg
Height (h) = 1.25 m
Acceleration due to gravity (g) = 9.8 m/s^2 (assuming standard gravity)
Now we can substitute the values into the formula:
Gravitational Potential Energy = 8.0 kg * 9.8 m/s^2 * 1.25 m
Calculating this:
Gravitational Potential Energy = 98 J
So the gravitational potential energy of the textbook-Earth system relative to the desk is 98 Joules.