Answer:
The existance of dark energy was suggested to help explain measurements, using Type Ia supernovae as distance indicators, that the expansion of the universe is speeding up and its acceleration requires a source of energy. Scientists suggested that It may be a new form of energy for which there is not yet a theoretical explanation. quantum mechanics predict that it may be the vacuum energy associated with "empty" space itself.
5m
Explanation:
Given parameters:
Weight of object = 50N
Work done in lifting object = 250J
Unknown:
Vertical height = ?
Solution:
The work done on an object is the force applied to lift a body in a specific direction.
Work done = force x distance
Weight is a force in the presence of gravity;
Work done = weight x height of lifting
Height of lifting = 
Height of lifting =
= 5m
The vertical height through which the object was lifted is 5m
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Answer:
Option A
Explanation:
At segment T-U, the substance changes from a liquid to a gas and does not change temperature.
The reason is because latent heat of vaporisation allows for the absorption of heat in the change of state and temperature remains constant until it has fully changed state.
The correct answers are <span>starting friction and </span>static friction
Friction slows down all forces, but starting friction slows down or stops completely the start of motion.