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3 years ago

When designing an experiment, why is it important to test only one variable?

Physics

2 answers:

m_a_m_a [10]3 years ago

6 0

That's the only way you can get consistent and accurate results.

zheka24 [161]3 years ago

6 0

I will try to explain more in depth. Lets say Jimmy frequently has headaches and needs medicine to treat it. Jimmy uses Headfix and Achefix both in one experiment. The next day, Jimmy feels great. His headaches are cured, but since Jimmy used 2 variables (the 2 medicines), he is left with three options

a. Headfix worked
b. Achefix worked
c. Both worked.

Now Jimmy has no idea what solved his problem. It could be 3 possible answers. However, if he used one variable at a time and had two experiments instead, lets see what happens.

Jimmy uses Headfix.
a. It worked
b. It didn't work

Headfix did not work.

Next experiment Jimmy uses Achefix
a. It worked
b. It didn't work

Achefix worked.

Now instead of having three possible solutions, you have 1 definite answer experiment. Therefore you cannot use more than one variable because there could be multiple outcomes and you do not know which variable affected the results differently/

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A man has a mass of 66 kg on the earth. What is his weight.

LUCKY_DIMON [66]

Since force = mass X acceleration, then the force he excerts on the earth (aka his weight) equals his mass times the force of gravity.

Therefore
W = (66 kg) X (9.8 m/ss)
W = 646.8 kgm/ss

kg m/ss are also known as Newtons, so your answer is...

646.8 N

8 0

3 years ago

With countercurrent flow, diffusion happened in all regions of the filter. Explain why

jeka94

Answer:

When the blood and the dialysate are flowing in the same direction, as the the dialysate and the blood move away from the region of higher concentration of the urea, to a region distant from the source, the concentration of urea in the blood stream and in the dialysis reach equilibrium and diffusion across the semipermeable membrane stops within the higher filter regions such as II, III, IV or V

However, for counter current flow, as the concentration of the urea in the blood stream becomes increasingly lesser the, it encounters increasingly unadulterated dialysate coming from the dialysate source, such that diffusion takes place in all regions of the filter

Explanation:

3 0

4 years ago

Sort each item to the correct location,

Hitman42 [59]

Answer:

the orbits of the planets are elliptical

the sun is the center of the solar system

includes 9 planets

3 0

3 years ago

Taco Bell sells 6 Tacos for $9.00. Del Taco sells 4 tacos for $8.00. is a better deal, because it costs less per taco.

steposvetlana [31]

Answer:

I'd say taco bell is a better deal, because you get more tacos.

Explanation:

but that's just what I think

8 0

3 years ago

Read 2 more answers

g While hauling a log in the back of a flatbed truck, a driver is pulled over by the state police. Although the log cannot roll

irga5000 [103]

Answer:

The minimum coefficient of static friction required, µ = 0.10

Note. The question is incomplete. The complete question is given below:

While hauling a log in the back of a flatbed truck, a driver is pulled over by the state police. Although the log cannot roll sideways, the police claim that the log could have slid out the back of the truck when accelerating from rest. The driver claims that the truck could not possibly accelerate at the level needed to achieve such an effect. Regardless, the police write a ticket anyway and now the driver court date is approaching.

The log has a mass of m = 929 kg; the truck has a mass of M = 8850 kg. According to the truck manufacturer, the truck can accelerate from 0 to 55 mph in 23.0 seconds, but this does not account for the additional mass of the log. Calculate the minimum coefficient of static friction μs needed to keep the log in the back of the truck.

Explanation:

First, velocity in mph is converted to m/s

1 mph = 0.447 m/s

55 mph ≈ 24.6 m/s

The acceleration of the empty truck is a = v/t = 24.6 / 23 = 1.07 m/s²

Force that can be generated by the truck, F = ma

F = 8850kg * 1.07 m/s² = 9469.5 N

However, with the added mass of the log on it, the acceleration of the truck will become;

a = F / m = 9469.5 N / (8550+929)kg = 0.97 m/s²

Frictional force between the log and the truck = 0.97 m/s² * 929 kg = 901.13 N

Normal reaction on the truck due to the weight of the log, R = mg

R = 929 kg * 9.8m/s² = 9104.2 N

Coefficient of static friction, µ = F/R

µ = 901.13/9104.2

µ = 0.098 ≈ 0.10

Therefore, the minimum static friction required is µ = 0.10

8 0

3 years ago