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:
Step-by-step explanation:
Given a Parabola that intersects the x-axis at x=3 and x=9.
I presume you want to determine the equation of the parabola.
You can use this form:
Given roots of a parabola, the equation of the parabola is derived using the formula:
The equation of the parabola is:
Answer:
2/7
Step-by-step explanation:
this is because you can simply do the butterfly method and multiply 4 times 2 which is 8 for 2/7 and 7 times 1 for 1/4 which is 7 so 2/7 is greater than 1/4
Answer:
15x^2 - 9x - 42
Step-by-step explanation:
(3x+6)(5x+7)
15x^2 +21x - 30x -42
15x^2 - 9x - 42
Answer:
25+x=y
Step-by-step explanation:
First, we start as 25, the number of cards he has in his collection. Then we add x, the cards he receive. The sum is y.
