Answer:
The claim made by the researcher lacks the validity on basis of reasons as indicated in the explanation.
Step-by-step explanation:
The claim made by the researcher is not valid on basis of following reasons:
- Interacting variables are not mapped accurately. The additional variables as the health status of the volunteers, eating and fitness habits are not considered in the consideration. This results in a in complete validation.
- The placebo effect is not catered accordingly. As the half of the volunteers are taking nothing, this is not the direct influence of the placebo and thus double-blinded testing for placebo effect is to be ensured in future experiments.
- The environmental effects are not considered as the effect under study is dependent on the environmental effects, thus the claim is biased and the generalization is not valid.
Answer:
<u>Option D: A cylinder with a circumference of about 50 units</u>
Step-by-step explanation:
The rest of the question is the attached figure.
The square shown has a perimeter of 32 units. The square is rotated about line k. What shape is created by the rotation and what is the approximate circumference of the base? Circumference of a circle: C = 2πr
===================================================
Given: the perimeter of the square = 32
perimeter of a square is four times the length of its side
So, the side length of square = 32/4 = 8 units
The square is rotated about line k.
So, it will form a cylinder with radius 8 units.
Circumference of a circle = 2 π r
Where, r is the radius of the circle.
Circumference of the base is C = 2 π * 8
∴ C = 16π = 16 * 3.14
∴ C = 50.26548 ≈ 50
The shape is created by the rotation is a cylinder with a circumference of about 50 units.
<u>So, the answer option is D.</u>
Answer: 
Step-by-step explanation:
You need to used the following formula:

Where "V" is the speed, "d" is the distance and "t" is the time.
In this case you know that Kevin traveled at a constant speed on the highway from Hickory Hills to Chicago in 20 minutes (which is
) and the distance is 17 miles. Then, you can identify that:

Therefore, knowing these values, you can substitute them into the formula. Then, you get:
Answer:
B. 90 + 90 √2
Step-by-step explanation:
From first base to the second base, it will travel 90 feet.
From the second base to the home plate, it will travel a longer distance. How much? Well, if you look at the layout of the field, you'll see that if you draw a line from second base to the home plate, you'll form two rectangular triangles, one with the 1st base, another one with the 3rd base.
The line from the 2nd base to home plate is the hypotenuse, which we can easily find by:
h²=90² + 90²
h = √(2 * 90²)
h = 90 √2
So, from second base to home plate, the ball has traveled 90 √2
Overall: 90 + 90 √2