Answer:
D. Test a piece of treated iron and a piece of untreated iron under the same conditions.
Explanation:
A controlled experiment is defined as an experiment where the experimenter or the researcher tries to test or experiment his result by changing one variable at a time and keeping the other factors under the same conditions and sees how it effects the result.
The factors which can be changed in an experiment is called its variables.
In the context, testing a piece of treated iron as well as a untreated piece of iron under the same working conditions forms a controlled experiment.
Watersheds provide many of us with our drinking water supply, plus recreational opportunities and aesthetic beauty. Watersheds are areas from which water runs into a public water supply. Thus, much of the water you drink from a public source has passed through a watershed. Because of this, it's important that care be taken to minimize any contaminents that may find their way into a public water supply. A small example of a watershed would be the hills around a reservoir. A larger example would be the portions of Pennsylvania, New York, Virginia, Maryland, Delaware and Washington DC that are designated Chesapeake Bay watershed.
3. It is not changing at that time
Explanation:
If the acceleration of a body is zero at some instant in time, it implies that the velocity is not changing at that point in time. Velocity is the rate of change of displacement with time.
✓Acceleration and velocity shares a very close relationship.
✓ For a body to accelerate, the velocity must change. Acceleration is defined as the rate of change of velocity with time.
✓If at any point, a body moves with constant velocity i.e the velocity does not change with time, the acceleration becomes zero.
✓ For acceleration to occur, a body must change velocity.
Learn more:
Acceleration brainly.com/question/6323625
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Answer:
1.11 s.
Explanation:
From the question given above, the following data were obtained:
Height (H) = 6 m
Acceleration due to gravity (g) = 9.8 m/s²
Time (t) =.?
The time taken for the branch to hit the ground can be obtained as follow:
H = ½gt²
6 = ½ × 9.8 × t²
6 = 4.9 × t²
Divide both side by 4.9
t² = 6/4.9
Take the square root of both side
t = √(6/4.9)
t = 1.11 s
Therefore, it will take 1.11 s for the branch to hit the ground.
