Answer:
The first law of thermodynamics is the law of conservation of energy. It states that energy is always conserved. ... To keep a machine moving, the energy applied should stay with the machine without any losses. Because of this fact alone, it is impossible to build perpetual motion machines.
Explanation:
Answer:

Explanation:
The energy of a photon is given by:

where
is the Planck constant
is the frequency of the photon
Substituting the numbers into the equation, we find:

Answer:
Because the rope is stopping the force of gravity from acceleration it.
PLZ MARK BRAINLIEST :-)
I think the answer is c chemical change
Answer:84Nm
Explanation:
force=400N
Distance=0.210m
Workdone=force x distance
Workdone=400 x 0.210
Workdone=84Nm