1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
nignag [31]
4 years ago
12

Experiment 1: A study is done to determine which of two fuel mixtures allows a rocket to travel farther over a period of time. R

ocket A, which requires additional equipment to keep it stable, is used to test one fuel mixture, and rocket B is used to test the other. Both rockets are identical aside from their mass. The results indicate that rocket B traveled farther than rocket A over the same period of time. Experiment 2: A double-blind experiment is performed to test whether a new drug is effective in lowering blood pressure. A random sample of subjects with high blood pressure is assigned to two groups. One group receives the new drug and the other group does not. Neither group is permitted to take any other medications during the experiment or to change their lifestyles in any way. The results of the experiment show that the drug is effective in lowering blood pressure.
Identify the experiment in which confounding occurs and the reason for its occurrence.

a. Neither experiment has a confounding variable.
b. Experiment 1 has a confounding variable related to the fuel mixtures. Varying the fuel mixture could skew the results of the study and should be kept constant.
c. Experiment 2 has a confounding variable related to the type of experiment. A double-blind experiment may increase the risk of the placebo effect and possibly skew the results.
d. Experiment 1 has a confounding variable related to the mass of the rockets. Any variation in mass may cause a discrepancy in the distance traveled.
e. Experiment 2 has a confounding variable related to the subjects used. Choosing a sample of subjects with high blood pressure instead of individuals with different blood pressure levels may confuse the results.
Physics
1 answer:
leva [86]4 years ago
3 0

Answer: D

Experiment 1 has a confounding variable related to the mass of the rockets. Any variation in mass may cause a discrepancy in the distance traveled.

This is the answer to the question because:

  • Both experiments do have a confounding variable.
  • Experiment 1 doesn't have to stay constant.
  • A double-blind experiment will not do anything to the placebo.
  • High blood pressure people will not make the results confusing.

The answer has to be the option D. Hope this helps you!

You might be interested in
When temperature decreases but actual water vapor content remains the same, what happens to relative humidity?
ruslelena [56]

Answer:

d. Relative humidity increases.

Explanation:

The expression of relative humidity in terms of absolute humidity, absolute pressure and saturation pression at measured temperature is:

\phi = \frac{\omega \cdot P}{(0.622+\omega)\cdot P_{sat}}

When temperature decreases, the saturation pressure decreases also and, consequently, relative humidity increases. Therefore, the right answer is option D.

8 0
3 years ago
Read 2 more answers
What is the amount of thermal energy needed to make 5 kg of ice at - 10 °C to
agasfer [191]

Answer:

The amount of thermal energy needed is 15167500 joules.

Explanation:

By First Law of Thermodynamics, we see that amount of thermal energy (Q), in joules, is equal to the change in internal energy. From statement we understand that change in internal energy consisting in two latent components (U_{l,ice}, U_{l,steam}), in joules, and two sensible component (U_{s,w}), in joules, that is:

Q = U_{l,ice} + U_{s, w} + U_{s,ice} + U_{l,steam} (1)

By definitions of Sensible and Latent Heat, we expanded the formula:

Q = m\cdot (h_{f,w}+h_{v,w}+c_{ice}\cdot \Delta T_{ice}+c_{w}\cdot \Delta T_{w}) (2)

Where:

m - Mass, in kilograms.

h_{f,w} - Latent heat of fussion of water, in joules per kilogram.

h_{v,w} - Latent heat of vaporization of water, in joules per kilogram.

c_{ice} - Specific heat of ice, in joules per kilogram per degree Celsius.

c_{w} - Specific heat of water, in joules per kilogram per degree Celsius.

\Delta T_{ice} - Change in temperature of ice, measured in degrees Celsius.

\Delta T_{w} - Change in temperature of water, measured in degrees Celsius.

If we know that m = 5\,kg, h_{f,w} = 3.34\times 10^{5}\,\frac{J}{kg}, h_{v,w} = 2.26\times 10^{6}\,\frac{J}{kg}, c_{ice} = 2.090\times 10^{3}\,\frac{J}{kg\cdot ^{\circ}C}, c_{w} = 4.186\times 10^{3}\,\frac{J}{kg\cdot ^{\circ}C}, \Delta T_{ice} = 10\,^{\circ}C and \Delta T_{w} = 100\,^{\circ}C, then the amount of thermal energy is:

Q = 15167500\,J

The amount of thermal energy needed is 15167500 joules.

7 0
3 years ago
A technician wearing a brass bracelet enclosing area 0.00500 m2 places her hand in a solenoid whose magnetic field is 3.10 T dir
aliya0001 [1]

Explanation:

Given that,

Area enclosed by a brass bracelet, A=0.005\ m^2

Initial magnetic field, B_i=3.1\ T

The electrical resistance around the circumference of the bracelet is, R = 0.02 ohms

Final magnetic field, B_f=0.93\ T

Time, t=16\ ms=16\times 10^{-3}\ s

The expression for the induced emf is given by :

\epsilon=-\dfrac{d\phi}{dt}

\phi = magnetic flux

\epsilon=-\dfrac{d(BA)}{dt}

\epsilon=-A\dfrac{d(B)}{dt}

\epsilon=-A\dfrac{B_f-B_i}{t}

\epsilon=-0.005 \times \dfrac{0.93-3.1}{16\times 10^{-3}}

\epsilon=0.678\ volts

So, the induced emf in the bracelet is 0.678 volts.

Using ohm's law to find the induced current as :

V = IR

I=\dfrac{V}{R}

I=\dfrac{0.678}{0.02}

I = 33.9 A

or

I = 34 A

So, the induced current in the bracelet is 34 A. Hence, this is the required solution.

5 0
3 years ago
HELP WILL MEDAL !!! if you give a inpproper statement you will be repoted
ehidna [41]
1: Weather has a somewhat unpredictable pattern.
2: They can misinterpret the pattern of weather that looks like snow.
3: If they predict it early then the weather can change making there interpretation wrong.

Hope that helps a little bit. Please don’t report me I tried.
8 0
3 years ago
A lady walks 10 m to the north, then she turns and continues walking 30 m due east.
ANEK [815]

Answer:

The distance covered is 40 m and the displacement is 31,6m.

Explanation:

The distance covered is the sum of the two distances (10+30). The displacement is equal to the distance of the hipotenusa of the triangle that the two distances (10 m to north and 30m to east) create. Using the Pythagoras theorem the displacent is equal to the Square root of (30^2 +10^2) .

4 0
3 years ago
Other questions:
  • 1. How are velocity, time, and acceleration<br> related mathematically?
    8·1 answer
  • A flat, rectangular coil consisting of 60 turns measures 23.0 cmcm by 34.0 cmcm . It is in a uniform, 1.40-TT, magnetic field, w
    10·1 answer
  • In a hospital setting, which of the following presents the possibility of being the source of an arc flash?
    9·1 answer
  • What is the pressure ratio for a sound that is 90 dB SPL?
    14·1 answer
  • ____ have more energy than ____. A. Radio waves; microwaves B. Ultraviolet rays; X-Rays C. Gamma rays; infrared rays D. Radio wa
    8·1 answer
  • If the end points are -8 and 12 what is the midpoint
    10·1 answer
  • Waves are often caused by
    15·2 answers
  • A soccer ball is kicked from the ground with an initial speed of 20.1 m/s at an upward angle of 47.8˚. A player 53.0 m away in t
    5·1 answer
  • Kinematics Question Please Help.
    5·1 answer
  • It is now 9:11 a.m. but when the bell rings at 9:12 a.m. Susie will be late for Mrs. Garner's U.S. History class for the 3rd tim
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!