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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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Toon Train is traveling at the speed of 10 m/s at the top of a hill. Five seconds later it reaches the bottom of the hill and is

Naddika [18.5K]

Answer:

the rate of acceleration of the train is 4 m/s²

Explanation:

Given;

initial velocity of the train, u = 10 m/s

change in time of motion, dt = 5 s

final velocity of the train, v = 30 m/s

The rate of acceleration of the train is calculated as;

$a = \frac{dv}{dt} = \frac{v-u}{dt} = \frac{30-10}{5} = \frac{20}{5} = 4 \ m/s^2$

Therefore, the rate of acceleration of the train is 4 m/s²

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2 years ago

Attempt 3 of 2

Wewaii [24]

Answer:

mass.

Explanation:

other physical factors are changeable but the mass of a particular substance is always constant.

6 0

3 years ago

Falls resulting in hip fractures are a major cause of injury and even death to the elderly. Typically, the hip’s speed at impact

Westkost [7]

Answer:

-5.8868501529 m/s² or -5.8868501529g

0.118909090909 s

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration

g = Acceleration due to gravity = 9.81 m/s²

$v^2-u^2=2as\\\Rightarrow a=\dfrac{v^2-u^2}{2s}\\\Rightarrow a=\dfrac{1.3^2-2^2}{2\times 0.02}\\\Rightarrow a=-5.8868501529\ m/s^2$

Dividing by g

$\dfrac{a}{g}=\dfrac{-57.75}{9.81}\\\Rightarrow a=-5.8868501529g$

The acceleration is -5.8868501529 m/s² or -5.8868501529g

$v=u+at\\\Rightarrow t=\dfrac{v-u}{a}\\\Rightarrow t=\dfrac{1.3-2}{-5.8868501529}\\\Rightarrow t=0.118909090909\ s$

The time taken is 0.118909090909 s

7 0

2 years ago

Chemical changes occur as energy is transferred when molecules- - or - to form one or more new substances

timurjin [86]

Answer:

Correct options are C. As food is digested, molecule bonds are broken, allowing new molecules to form that can be used by our bodies.

D. Energy stored in organic fuels are used for heat and electricity/ When batteries are connected to a circuit, a reaction occurs inside the cell producing electrical energy.

Explanation:

The breakdown of food leads to the release of chemical energy which was first stored in food. This energy is used to drive necessary functions of the body. A series of chemical reactions are involved in the breakdown of food and changing them into useful components for the cell.

Chemical energy is stored in circuits. When the battery is connected to a circuit, the chemical energy gets transferred into electrical energy.

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3 years ago

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What is the law of inertia? Give an example of inertia in action.

belka [17]

Answer

Inertia is the resistance of any physical object to any change in its velocity. This includes changes to the object's speed, or direction of motion. An aspect of this property is the tendency of objects to keep moving in a straight line at a constant speed, when no forces act upon them.

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2 years ago

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