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nignag [31]
3 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]3 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!

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A container of soy milk has the instructions on its label to “shake well before opening ” The soy milk is most likely a ?
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4 0
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An ideally efficient heat pump delivers 1000 J of heat to room air at 300 K. If it extracted heat from 260 K outdoor air, how mu
choli [55]

Answer:

Wnet, in, = 133.33J

Explanation:

Given that

Pump heat QH = 1000J

Warm temperature TH= 300K

Cold temperature TL= 260K

Since the heat pump is completely reversible, the combination of coefficient of performance expression is given as,

From first law of thermodynamics,

COP(HP, rev) = 1/(1-TL/TH)

COP(HP, rev) = 1/(1-260/300)

COP(HP, rev) = 1/(1-0.867)

COP(HP, rev) = 1/0.133

COP(HP, rev) = 7.5

The power required to drive the the heat pump is given as

Wnet, in= QH/COP(HP, rev)

Wnet, in = 1000/7.5

Wnet, in = 133.333J. QED

So the 133.33J was the amount heat that was originally work consumed in the transfer.

Extra....

According to the first law, the rate at which heat is removed from the low temperature reservoir is given as

QL=QH-Wnet, in

QL=1000-133.333

QL=866.67J

5 0
3 years ago
A supertanker ( = 1.70 × 108 kg) is moving with a constant velocity. Its engines generate a forward thrust of 7.40 × 105 N. Dete
a_sh-v [17]

Answer:

(a) 0 (b) F=1.67\times 10^9\ N

Explanation:

Given that,

Mass of a supertanker, m=1.7\times 10^8\ kg

The engine of a generate a forward thrust of, F=7.4\times 10^5\ N

(a) As the supertanker is moving with a constant velocity. We need to find the magnitude of the resistive force exerted on the tanker by the water. It is given by :

F = ma, a is the acceleration

For constant velocity, a = 0

So, F = 0

(b) The magnitude of the upward buoyant force exerted on the tanker by the water is equal to the weight of the ship.

F = mg

F=1.7\times 10^8\times 9.8\\\\F=1.67\times 10^9\ N

Hence, this is the required solution.

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The independent variable would be the shirts you are using the dependent variable would be the detergent.

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