It takes 86 joules of energy to raise a box 2 meters using the pulley setup shown above.

Without the pulley, the box can be raised 2 meters using only 82 joules of energy. What could explain this 4-joule difference?

A.
When raising the box using the pulley, 4 joules of mechanical energy are broken down into protons, neutrons, and electrons.
B.
When raising the box using the pulley, 4 joules of mechanical energy are transformed into water.
C.
When raising the box using the pulley, 4 joules of mechanical energy are converted into heat energy due to friction.
D.
When raising the box using the pulley, 4 joules of mechanical energy are destroyed.

The answer is C, when raising the box using the pulley, 4 joules of mechanical energy are converted into heat energy due to friction. :)

Explanation:

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.