Answer:
In a controlled experiment, an independent variable (the cause) is systematically manipulated and the dependent variable (the effect) is measured; any extraneous variables are controlled. The researcher can operationalize (i.e. define) the variables being studied so they can be objectivity measured.
Answer:
Kepler's Third Law
T = 2 π r 3 G M E . T = 2 π r 3 G M E . For an ellipse, recall that the semi-major axis is one-half the sum of the perihelion and the aphelion. For a circular orbit, the semi-major axis (a) is the same as the radius for the orbit.
Answer:
a) They are the same.
Explanation:
Assuming no friction, there should be no energy transfer and thus the Law of Conservation of Energy says:

These types of problems also disregard any air resistance the surface of the object may cause. Therefore, no energy is transferred and from the Law of Conservation of Energy,
of energy is preserved.
The traveled distance of the car from the initial point is (4+7) Km, i.e., 11 Km.
Answer:
400 years
Explanation:
The equation that describes the decay of a radioactive sample is:
(1)
where
m(t) is the amount of sample left at time t
is the initial amount of the sample
is the half-life, which is the time taken for the sample to halve
In this problem we have:
is the half-life of Nickel-63
After a time t, the amount of sample left is 6.25% of the original one, which means that

So we can rewrite the equation (1) and solving for t to find the time:
