Question 1145905: A car is traveling at a constant speed in a tunnel, up a 1-percent grade. If the car and passenger weigh 12.4 kN, what attractive force must the engine supply to just overcome the component of the gravitational force on the car along the bottom of the tunnel?
Answer by ikleyn(52814)   (Show Source):
You can put this solution on YOUR website! .
From the Internet, https://www.thefreedictionary.com/attractive+force
attractive force - the force by which one object attracts another.
Obviously, it is incorrect using this term in the problem. (Attractive force is the term from Gravitation.)
In the condition, simply OMIT this term "attractive" as IRRELEVANT.
Make a sketch or look into my lesson
- Using vectors to solve problems in Mechanics: Force, Figures 3, 4 and 5.
in this site.
From this lesson (or from elementary consideration), the magnitude of the force under the question is
| F | =  ,
where W is the weight,  is the angle of the tunnel floor with the horizon.
We are given  = 1% = 0.01 (one percent grade).
It is so small grade that approximately  = ( ! APPROXIMATELY, with very good precision).
Therefore, | F | = w*0.01 = 12.4 kN * 0.01 = 12400 Newtons * 0.01 = 124 Newtons. ANSWER
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