It's difficult to make out what the force and displacement vectors are supposed to be, so I'll generalize.
Let <em>θ</em> be the angle between the force vector <em>F</em> and the displacement vector <em>r</em>. The work <em>W</em> done by <em>F</em> in the direction of <em>r</em> is
<em>W</em> = <em>F</em> • <em>r</em> cos(<em>θ</em>)
The cosine of the angle between the vectors can be obtained from the dot product identity,
<em>a</em> • <em>b</em> = ||<em>a</em>|| ||<em>b</em>|| cos(<em>θ</em>) ==> cos(<em>θ</em>) = (<em>a</em> • <em>b</em>) / (||<em>a</em>|| ||<em>b</em>||)
so that
<em>W</em> = (<em>F</em> • <em>r</em>)² / (||<em>F</em>|| ||<em>r</em>||)
For instance, if <em>F</em> = 3<em>i</em> + <em>j</em> + <em>k</em> and <em>r</em> = 7<em>i</em> - 7<em>j</em> - <em>k</em> (which is my closest guess to the given vectors' components), then the work done by <em>F</em> along <em>r</em> is
<em>W</em> = ((3<em>i</em> + <em>j</em> + <em>k</em>) • (7<em>i</em> - 7<em>j</em> - <em>k</em>))² / (√(3² + 1² + 1²) √(7² + (-7)² + (-1)²))
==> <em>W</em> ≈ 5.12 J
(assuming <em>F</em> and <em>r</em> are measured in Newtons (N) and meters (m), respectively).
Answer:
9/2
Step-by-step explanation:
perpendicular lines have slopes that are opposite and reciprocal
the reciprocal of -2/9 is 9/2
Answer:
Step-by-step explanation:
32 is equivalent to 64 because 3 x 4 = 2 x 6 = 12. 96 is equivalent to 64 because 9 x 4 = 6 x 6 = 36. 128 is equivalent to 64 because 12 x 4 = 8 x 6 = 48.
Answer:
True
Step-by-step explanation:
This equation correctly represents the total cost of the food that the friends ended up paying for the popcorn and sodas. In this expression, the cost of each individual soda is represented by the variable x which is multiplied by 4 since each one of the four friend's purchased their own soda. After making this multiplication process that product is added to the initial $12 that they all spent together on the popcorn.
