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Oxana [17]
3 years ago
12

if a material has a half-life of 24 hours, how long do you have to wait until the amount of radioisotope is 1/4 its original amo

unt?
Physics
1 answer:
7nadin3 [17]3 years ago
3 0

Answer:

48 hours

Explanation:

Using the formula,

R/R' = 2ᵃ/ᵇ..................... Equation 1

Where R = Original amount, R' = Radioactive remain, a = Total time, b = half life.

Given: b = 24 hours,

Let: R = X, then R' = X/4.

Substitute into equation 1

X/(X/4) = 2ᵃ/²⁴

4 = 2ᵃ/²⁴

2² = 2ᵃ/²⁴

Equating the base and solving for a

2 = a/24

a = 24×2

a = 48 hours.

Hence the time = 48 hours

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vector u has a magnitude of 20 and direction of 0°.vector v has amagnitude of 40and a direction of 60°.find the magnitude and di
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Addition of vectors:

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Vector Sum:

The resultant of two vectors is simply the vector sum of the vectors. There are a handful of ways to present the resultant factor; the notation that shows the vector magnitude and direction is called the polar vector notation. An example of a vector presented in polar vector notation is

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Answer and Explanation:

Let's first present the vectors in rectangular vector notation.

For the vector →u of magnitude 20 and direction 0∘ to the horizontal axis, the vector is →u=^i20.

For the vector →v

of magnitude 40 and direction 60∘ to the horizontal axis, the vector is →v=^i40cos60∘+^j40sin60∘.

The resultant vector →w is the vector sum of the vectors, i.e.

→w=→u+→v

=^i20+^i40cos60∘+^j40sin60∘

=^i(20+40cos60∘)+^j(40sin60∘)

=^i40+^j20√3

For a vector ^ix+^jy, the magnitude of the vector is √x2+y2 and the direction above the horizontal axis is θ=tan−1(yx).

Let's use the formulas:

|→w|∠θ=√(40)2+(20√3)2∠tan−1(20√340)≈52.9∠40.9∘

The magnitude of the vector is about 53 units in the direction 41-degrees above the horizontal axis.

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1 year ago
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Answer:

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e. Energy stored in the capacitor

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3 years ago
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