Answer:
The correct reaction force in response to Heidi's action force is:
c. The friction is equal to 660 N since the beam is not accelerating.
Explanation:
Heidi's action force does not affect the beam. Since friction resists the sliding or rolling of one solid object over another, there is no friction acting on the beam, in this respect. The reaction force is what makes the dog to move because it acts on it. According to Newton's Third Law of Motion, forces always come in action-reaction pairs. This Third Law states that for every action force, there is an equal and opposite reaction force. This means that the dog exerts some force on Heidi, as he pulls it "forward with a force of 9.55 N."
The answer might be B because the value is negative, and negative could mean slowing down.
Answer:

Explanation:
The formula for potential energy is:

where <em>m </em>is the mass, <em>g</em> is the gravitational acceleration, and <em>h</em> is the height.
The mass of the book is 0.4 kilograms. The gravitational acceleration on Earth is 9.8 m/s². The height of the book is 2 meters.

Substitute the values into the formula.

Multiply the first two numbers.
- 0.4 kg*9.8 m/s²= 3.92 kg*m/s²
- If we convert the units now, the problem will be much easier later on.
- 1 kg*m/s² is equal to 1 Newton. So, our answer of 3.92 kg*m/s² is equal to 3.92 N

Multiply.
- 3.92 N* 2 m=7.84 N*m
- 1 Newton meter is equal to 1 Joule (this is why we converted the units).
- Our answer is equal to<u> 7.84 Joules.</u>

A research question that would complete the third question you need that are related to the first 2 questions which are:
- “what type of masks help prevent fog on glasses when breathing?”
- “does a mask’s material affect the level of fog on glasses as an effect of breathing?”
Would be: "Are there any available masks that could prevent fog on glasses that could be improved upon"?
This new research question would help you find out if there is an already existing mask that could be made better.
<h3>What is a Research Question?</h3>
This refers to "a question that a research project sets out to answer". and seeks to give answers to particular phenomena.
Hence, we can see that the new research question Would be: "Are there any available masks that could prevent fog on glasses that could be improved upon"?
This new research question would help you find out if there is an already existing mask that could be made better.
Read more about research questions here:
brainly.com/question/25257437
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