Answer:
a.
b.1058 N
Explanation:
We are given that
Mass of each dog,M=18.5 kg
Mass of sled with rider,m=250 kg
a.Average force,F=185 N


By Newton's second law



b.By Newton's second law

Substitute the values

Hence, the force in the coupling between the dogs and the sled=1058 N
The amount of gravitational potential energy acquired by the rock is equal to:

where
m is the mass of the rock
g is the gravitational acceleration

is the increase in height of the rock
Substituting the data of the problem, we find

So, Natalie gave 220.7 J of energy to the rock.
Subjective questions can be answered most likely through well-designed scientific investigations. Investigating peoples opinions or favorites does not involve any scientific investigations.
<h3>What are scientific investigation?</h3>
Scientific investigations include study on different natural phenomenon through well designed research methodologies. They include a preliminary hypothesis based on observations and various scientific records helps for reference.
Through well designed scientific experiments we can solve subjective questions and can be helpful in solving different environmental or social issues.
Peoples opinion or objective types questions are not targeted at scientific investigation, hence, option b is correct.
To find more on scientific investigations, refer here:
brainly.com/question/8386821
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