Answer:
Step-by-step explanation:
chemical energy of 1 kg coal is 3 million joules .
If this energy is used to lift one kg of coal , let height attained be h
chemical energy = gravitational energy of 1 kg of coal
3 x 10⁶ = m g h = 1 x 10 x h
h = 3 x 10⁵ m
= 300 x 10³ m
= 300 km .
i kg coal can be lifted by height of 300 km .