He has a mass of 56 kg.
The equation given is PE = mgh.
PE = 4620 J
h = 8.4
g = 9.8
Therefore:
4620 = 82.32m
m = 4620/82.32
m = 56 (rounded to two significant digits)
Most of the time the towns get flooded and many people die and lose their homes and their jobs, businesses by the floods and the natural environment is destroyed ,air pollution is produced, the ecosystem could be disrupted and dams are known to fall over and dams are really expensive to build, The dams also cause geological damage, example earthquakes and spills happen.
Answer: She is incorrect to conclude that the reaction is endothermic.
As in the second trial, the temperature has increased by 20 °C , that means the heat has been released and energy is released in exothermic reactions.
Exothermic reactions: The reactions in which the energy of the products is less than the energy of the reactants, and the excess energy is released as heat.
Endothermic reactions: The reactions in which the energy of the products is more than the energy of the reactants, and the excess energy is absorbed as heat.
AuthenticD3mon and I talked it over and agreed that
natural gas is the least polluting fossil fuel.
(See comments under his answer.)