Answer: 4
The mechanical advantage is the ratio of the force exerted by the object to the force applied to do work on it.
Here, Jeff tried to lift a rock weighing 600 pounds by wedging board under the rock. Jeff who weighs 150 pounds uses all his weight to exert force on lever and lift rock.
Mechanical advantage, 
Therefore, the mechanical advantage that lever provided to Jeff in lifting rock is 4.
Kinematics : Study of motion
Fluid kinematics : study of how fluid flows and how to describe its motion.
There are two ways to describe fluid motion
one is Eulerian, where the variations are described at all fixed stations as a function of time.
the other is Lagrangian, in which one follows all fluid particles and describes the variations around each fluid particle along its trajectory.
<u>DIFFRENCE BETWEEN LAGRANGIAN AND EULERIAN:</u>
1.Both Lagrangian and Eulerian describes time variation.
2. Eulerian describes the rate of change in one point of space
Lagrangian descries rate of change of a property of material system.
To know more about the Lagrangian and Eulerian :\brainly.com/question/14944792
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The IRB at the university will decide whether her study meets ethical guidelines before it is initiated. The importance of these codes of conduct is to safeguard research participants, the status of psychology and the researchers or psychologists themselves. Moral issues hardly yield a simple, unequivocal, right or wrong answer. It is consequently often a matter of judgment whether the research is justified or not. For instance, it might be that a study roots psychological or physical uneasiness to participants, maybe they agonize pain or maybe even come to solemn harm.
The answer is b fission hope this helps