D. 23/30 This is saying that out of 30 days, 23 of them she saw a ladybug, which means that each day, there is a 23/30 chance of finding one.
Answer:
B - 181/500
Step-by-step explanation:
To convert percentages to fractions you divide by 100. That would make this 36.2/100. But we dont like fractions with decimal points in so you would multiply the whole thing by 5 to get rid of the .2 this makes the answer 181/500
Answer: 600 students
Step-by-step explanation:
Of the total number of sixth graders who were surveyed, 5% owned birds.
This 5% translated to 30 students.
30 students is therefore 5% of the total number of sixth graders surveyed.
Assume that number to be x:
x * 5% = 30
x = 30 / 5%
= 600 students
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).
