When Emmett is lifting a box
vertically, the forces that must be added to calculate the total force are: the
gravitational force, tension force(the force exerted by Emmett to the box and
the force exerted by the box to Emmett), and air resistance force.
The correct answer is:
<span>B.) At terminal velocity there is no net force
In fact, when the parachutist reaches the terminal velocity, his velocity does not change any more. It means that the acceleration acting on the parachutist is zero, and for Newton's second law, this means the net force acting on him is zero:
</span>
![\sum F = ma = 0](https://tex.z-dn.net/?f=%5Csum%20F%20%3D%20ma%20%3D%200)
<span>because the acceleration is zero: a=0.
This also means that the two relevant forces acting on the parachutist (gravity, downward, and air resistance, upward) are balanced to produce a net force equal to zero.</span>
When developing an experimental design, the action that would improve the quality of the results is to ensure that it answers a question about cause and effect.
<h3>What is experimental design?</h3>
Experimental design is a concept used to organize, conduct, and interpret results of experiments in an efficient way, making sure that as much useful information as possible is obtained by performing a small number of trials.
Thus, when developing an experimental design, the action that would improve the quality of the results is to ensure that it answers a question about cause and effect.
Learn more about experimental design here: brainly.com/question/17274244
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Answer:
maybe its heat sorry if it's wrong
because if friction is not in the problem so we are making heat or thermal energy
The best answer to this question is D. a god scientific question should be based on observations instead of just imagination.
Hope this helps.