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aleksklad
3 months ago
11

What is the number N0 of 99mTc atoms that must be present to have an activity of 15mCi?

Physics
1 answer:
Keith_Richards [3.2K]3 months ago
4 0
Based on my findings, within a period of 2 hours, there are certain atoms remaining. N = N0 * 2^(-t/6.020) = N = N0 * 2^-0.33223 = 0.7943 N0 Thus, the quantity of atoms that undergo disintegration is N0 - N = N0 * (1 - 0.79430) = 0.2057 N0 This must equate to 15 mCi = 15 * 3.7 * 10^7 = 5.55 * 10^8 atoms N0 = 5.55 * 10^8 / 0.2057 = 2.698 * 10^9 atoms Consequently, 2.698 * 10^9 atoms represents the value of N0.
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In a third class lever, the distance from the effort to the fulcrum is ____________ the distance from the load/resistance to the
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The full sentence states:
In a third class lever, the distance between the effort and the fulcrum is LESS than the distance between the load/resistance and the fulcrum.
In a third class lever, the fulcrum is positioned on one end of the effort, while the load/resistance is on the opposite side, placing the effort somewhere in between. Consequently, the distance from the effort to the fulcrum is less than that from the load to the fulcrum.
4 0
2 months ago
a pebble is dropped down a well and hits the water 1.5 seconds later. using the equations for motion with constant acceleration,
inna [3103]
Definamos h como la distancia que hay desde el borde del pozo hasta la superficie del agua (en metros).

Consideremos la gravedad g como 9.8 m/s² y despreciemos la resistencia del aire.

La velocidad inicial vertical del guijarro es nula.
Ya que el guijarro impacta el agua tras 1.5 segundos, entonces:
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Resultado: 11.025 m
7 0
3 months ago
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A horizontal jet of water is made to hit a vertical wall with a negligible rebound. If the speed of water from the jet is 'v', t
serg [3582]
F = π/4 ρ d² v²

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F = ma

Acceleration is defined as the change in velocity over the change in time:

F = m Δv / Δt

Since there is no rebound effect, Δv is equal to v.

F = m v / Δt

Mass can be calculated as density multiplied by volume:

F = ρ V v / Δt

Flow rate describes the volume per time:

F = ρ Q v

Flow rate is determined by velocity multiplied by the cross-sectional area:

F = ρ (v A) v

This simplifies to F = ρ A v²

The area of a circle is calculated as pi times the square of the radius, or as pi/4 times the diameter squared:

F = ρ (π/4 d²) v²

Hence, F = π/4 ρ d² v²

3 0
2 months ago
A 5 kg block moves with a constant speed of 10 ms to the right on a smooth surface where frictional forces are considered to be
Yuliya22 [3333]

Answer:

The work done, W = 19.6 J

Explanation:

It’s provided that

The mass of the block, m = 5 kg

The velocity of the block, v = 10 m/s

The coefficient of kinetic friction between the block and rough surface is 0.2

Distance traveled by the block, d = 2 m

As the block traverses the rough section, it loses energy equal to the work done by the kinetic energy.

W=\mu_kmgd

W=0.2\times 5\times 9.8\times 2

W = 19.6 J

Thus, the change in kinetic energy of the block moving through the rough section is 19.6 J. Consequently, this is the required answer.

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2 months ago
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