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3 years ago

2. Why is an experiment called a controlled study?

2 answers:

5 0

An experiment is called a controlled study because the person conducting the experiment will be able to control the controllable variables or factors. The person conducting the experiment can manipulate the variables other than the independent variables and the number of times the experiment will be done.

rewona [7]3 years ago

3 0

An experiment is termed a controlled study as a result of the person conducting the experiment are going to be able to control the controllable variables or factors. The person conducting the experiment will manipulate the variables apart from the independent variables and therefore the variety of times the experiment are going to be done.

Explanation:
In a controlled exposure study, one cluster of participants is exposed to a substance (e.g. a pollutant) whereas those within the"control" group aren't. The results are then compared to work out the health effects of the substance being studied.

A controlled experiment could be a scientific test done underneath controlled conditions, which means that only one (or a few) factors are modified at a time, whereas all others are kept constant.

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A 2.20-kg object is attached to a spring and placed on frictionless, horizontal surface. A horizontal force of 29.0 N is require

g100num [7]

Answer:

a. 145 N/m b. 1.29 Hz c. 1.62 m/s d. 0 m e. 13.2 m/s² f. ± 0.2 m g. 2.9 J h. 0.54 m/s i. 4.39 m/s²

Explanation:

a. The force constant of the spring

The spring force F = kx and k = F/x where k is the spring constant. F = 29.0 N and x = 0.200 m

k = 29.0 N/0.200 m = 145 N/m

b. The frequency of oscillations, f

f = 1/2π√(k/m) m = mass = 2.20 kg

f = 1/2π√(145 N/m/2.20 kg) = 1.29 Hz

c. maximum speed of the object

The maximum elastic potential energy of the spring = maximum kinetic energy of the object

1/2kx² = 1/2mv²

v = (√k/m)x where v is the maximum speed of the object

v = (√145/2.2)0.2 = 1.62 m/s

d Where does the maximum speed occur?

The maximum speed occurs at 0 m

e. The maximum acceleration

a = kx/m = 145 × 0.2/2.2 = 13.2 m/s²

f. The maximum acceleration occurs at x = ± 0.2 m

g. The total energy of the system is the maximum elestic potential energy of the system

E = 1/2kx² = 1/2 × 145 × 0.2² = 2.9 J

h. When x = x₀/3

1/2k(x₀/3)² = 1/2mv²

kx₀²/9 = mv²

v = 1/3(√k/m)x₀ = 1/3(√145/2.2)0.2 = 0.54 m/s

i When x = x₀/3

a = kx₀/3m = 145 × 0.2/(2.2 × 3)= 4.39 m/s²

8 0

3 years ago

Our milky way galaxy is 100000 lyly in diameter. a spaceship crossing the galaxy measures the galaxy's diameter to be a mere 1.

Sidana [21]

The speed of the spaceship relative to the galaxy is 0.99999995c.

A light-year measures distance rather than time (as the name might imply). A light-year is a distance a light beam travels in one year on Earth, which is roughly 6 trillion miles (9.7 trillion kilometers). One light-year equals 5,878,625,370,000 miles. Light moves at a speed of 670,616,629 mph (1,079,252,849 km/h) in a vacuum.We multiply this speed by the number of hours in a year to calculate the distance of a light-year (8,766).

The Milky way galaxy is 100,000 light years in diameter.

The galaxy's diameter is a mere 1. 0 ly.

We know that ;

$L = L_0 \sqrt{1-\frac{v^2}{c^2} }$

L = 1 light year

L₀ = 100,000 light year

$1 = 100,000 \sqrt{1-\frac{v^2}{c^2} }$

$1 = 100,000 \sqrt{1-\frac{v^2}{(3*10^8)^2} }$

$\frac{1}{100,000} = \sqrt{1-\frac{v^2}{c^2} }$

$v = 0.999999995$ $c$

Therefore, the speed of the spaceship relative to the galaxy is 0.99999995c.

Learn more about a light year here:

brainly.com/question/17423632

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5 0

2 years ago

A museum sets up a display of fluorescent minerals. Which best describes how electromagnetic waves can be used to enhance the di

Volgvan

Answer:c

Explanation:

4 0

3 years ago

How does the type of medium affect a sound wave?

Llana [10]

The type of medium affects a sound wave as sound travels with the help of the vibration in particles. As different mediums have different amount and size of particles, for example, the speed of sound is faster through solid than liquid as solids have closely packed particles whereas liquids are loosely packed. Therefore the vibration is quicker in solids than liquids.

Hope it helps you! :)

7 0

3 years ago

A charge of 90 C passes through a wire in 1 hour 15 minutes . what is the current in the wire

timurjin [86]

We calculate current from the formula:
$I= \frac{q}{t}$ , where q is a electric charge transferred over time t
Time should be converted to seconds:
1h 15 min= 75min= 4500s
I= $\frac{90C}{4500s}=0,02A$ Result is in unit-Ampere

5 0

3 years ago

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