Answer:
1.125
Explanation:
I think it is his because if you add 0.30 and 0.15 it adds up to 0.45 so you just multiply 0.45 and 2.5 and then it gives you 1.125. HOPE IT HELPS.
Answer:
Gravitational force of attraction.
Explanation:
When two bodies of masses 'm' and 'M' are separated by a distance 'r', then both the bodies experience a force of attraction towards each other. This force of attraction is called gravitational force. It is a weak force but it always act between two bodies that have mass.
The magnitude of the gravitational force is directly proportional to product of the masses and inversely proportional to the square of the distance between the masses.
This means that as the distance between the bodies is increases, the gravitational force between the bodies decreases and vice versa.
The gravitational force of attraction is given as:

The Supreme Court case of Marbury v. Madison
<span>(1803) strengthened the power of the judicial branch by</span> "<span>(4) granting federal courts the power to declare
laws unconstitutional"</span>
Half-life is the time taken for the concentration of the substance to reduce by 50%. The original sample of strontium had a mass of 1.6 gms. Thus, option d is correct.
<h3>What is half-life?</h3>
The half-life of any radioactive substance is the time period at which the concentration will get reduced to half the initial amount. The initial mass of Sr-90 is calculated as,

Given,
Quantity of the remaining substance N (t) = 0.40 gm
Initial radioactive substance quantity
=?
Time duration (t) = 56 years
Half-life = 28 years
Substituting values above:

= 1.6 gm
Therefore, option d. the initial mass of Sr is 1.6 gm.
Learn more about half-life here:
brainly.com/question/16145921
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Answer:
there is your answer hopefully it helps you out