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antoniya [11.8K]
3 years ago
12

If we start with 400 atoms of a radioactive substance, how many would remain after one half-life? After 2 half-lives? After 3 ha

lf-lives? After 4 half-lives?
Physics
1 answer:
AysviL [449]3 years ago
3 0

Answer:

how many would remain

after one half-life = 200 atoms

After 2 half-lives = 100 atoms

After 3 half-lives = 50 atoms

After 4 half-lives = 25 atoms

Explanation:

Given;

Initial amount = 400 atoms

Half life is the time taken to decay half of a radioactive material.

how many would remain after one half-life;

= 400/2 = 200 atoms

After 2 half-lives;

= 400/2^2 = 400/4

= 100 atoms

After 3 half-lives

= 400/2^3 = 400/8

= 50 atoms

After 4 half-lives

= 400/2^4 = 400/16

= 25 atoms

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Answer:

<h2>154.73N</h2>

Explanation:

The question is incomplete. Here is the complete question.

Using the strap at an angle of 31° above the horizontal, a Grade 12 Physics student, tired from studying, is dragging his 15 kg school bag across the floor at a constant velocity. (a) If the force of tension in the strap is 51 N, what is the normal force.

Check the diagram related to the question in the attachment below for better understanding.

The normal force is the reaction acting perpendicular to the force of tension in the strap and opposite the weight of the bag. They are the forces acting along the vertical.

The normal force N will be the sum of the force of tension acting along the vertical (Ty) and the weight of the bag (W).

Ty = 15sin31°

Ty = 7.73N

W = mass * acceleration due to gravity

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W = 147N

The normal force is therefore expressed as;

N = Ty + W

N = 7.73 + 147

N = 154.73N

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3 years ago
While watching a movie a spaceship explodes and there is a loud bang and flash of light. What is wrong with this scene? Explain
Ksenya-84 [330]
Well if the ship was in space their shouldn’t be a loud bang. Because you can’t hear anything in space
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2 years ago
A mechanic pushes a 2.30 ✕ 103-kg car from rest to a speed of v, doing 4,800 J of work in the process. During this time, the car
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The horizontal force applied is  160 N while the velocity is  2.03 m/s.

<h3>What is the speed of the car?</h3>

The work done by the car is obtained as the product of the force and the distance;

W = F x

F = ?

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W = 4,800 J

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F = 160 N

But F = ma

a = F/m

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Now;

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v = √2as

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The curve below shows the percentage of population of aquatic species that die in response to doses of pollutant A:
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  • Since the pollutant level is still increasing, then the spill level still need effective monitoring.

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In order for an object to have kinetic energy it must have a mass and a ?
almond37 [142]

Answer:

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  • The potential energy of a body is due to the height from the surface of the earth.

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