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3 years ago

Can someone help me? Idk why I can't understand this

Physics

1 answer:

olya-2409 [2.1K]3 years ago

5 0

It's been a while since I've studied this, but my answers would be:

13. 5730 years. The half-life of a substance is the amount of time it takes for half of it to decay, and, according to the graph, half of the substance remained at 5730 years.

14. 10740 years. According to the graph, only 25% of the carbon remained after 10740 years.

15. 15 atoms. According to the graph, only 12.5% of the carbon remained after 16110 years. 12.5% of 120 atoms is 15 atoms.

16. 1600 atoms. According to the graph, if a sample of carbon is 10740 years old, only 25% of it remains. To find the original amount, multiply the current amount by (100% / 25%), which equals 4. So, 4. 400 atoms * 4 = 1600 atoms is the original amount.

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HELP ME PLEASE!!!!!!!!!!!!!!!!!!!!!!!!!!!

soldi70 [24.7K]

Limestone, Sandstone, and Shale would be the answer.

4 0

4 years ago

A straight, vertical wire carries a current of 2.15 A downward in a region between the poles of a large superconducting electrom

enot [183]

Answer:

a) F = 0.01234N to the south direction

b) F = 0.01234N to the north direction

c) F = 0.01234N

d) North of West

Explanation:

The magnetic force in a magnetic field is given by:

$F = BIlsin \theta$

Length of the wire, l = 1 cm = 0.01 m

Current flowing through the wire, I = 2.15 A

a) If the magnetic field direction is east

∅ = 90

F = 0.574 * 2.15 * 0.01

F = 0.01234 N to the south direction according to the Fleming's Right Hand Rule

b) If the magnetic field direction is south

The magnitude of the magnetic force remains the same

That is , F = BIL sin 90

F = 0.01234 N to the west

c) If the magnetic field direction is 30 degrees south

The angle between the magnetic field and the length of the wire still remains 90 degrees

Therefore the magnitude of the force still remains 0.01234

F = 0.01234 N

d) the direction of the force is the North of West

8 0

3 years ago

A cabbie is trying to stop when he notices a fare is whistling them over. The

liberstina [14]

K.E=18750J
Mass=m=2100kg
Velocity=v

$\boxed{\sf K.E=\dfrac{1}{2}mv^2}$

$\\ \sf\longmapsto 18750=\dfrac{1}{2}2100v^2$

$\\ \sf\longmapsto 18750=1050v^2$

$\\ \sf\longmapsto v^2=\dfrac{18750}{1050}$

$\\ \sf\longmapsto v^2=17.85m^2$

$\\ \sf\longmapsto v=\sqrt{17.85}$

$\\ \sf\longmapsto v=4.1m/s$

7 0

3 years ago

One end of a metal rod is in contact with a thermal reservoir at 745. K, and the other end is in contact with a thermal reservoi

Masteriza [31]

Answer:

a) $S_1=-9.65}\ J/K$

b) $S_2=71.18\ J/K$

c) 0 J/K

d)S= 61.53 J/K

Explanation:

Given that

T₁ = 745 K

T₂ = 101 K

Q= 7190 J

The entropy change of reservoir 745 K

$S_1=-\dfrac{7190}{745}\ J/K$

Negative sign because heat is leaving.

$S_1=-9.65}\ J/K$

The entropy change of reservoir 101 K

$S_2=\dfrac{7190}{101}\ J/K$

$S_2=71.18\ J/K$

The entropy change of the rod will be zero.

The entropy change of the system

S= S₁ + S₂

S = 71.18 - 9.65 J/K

S= 61.53 J/K

3 0

4 years ago

A 100 N force is applied to a 50 kg crate resting on a level floor. The coefficient of kinetic friction is 0.15. What is the acc

Nookie1986 [14]

The acceleration of the crate after it begins to move is 0.5 m/s²

We'll begin by calculating the the frictional force

Mass (m) = 50 Kg

Coefficient of kinetic friction (μ) = 0.15

Acceleration due to gravity (g) = 10 m/s²

Normal reaction (N) = mg = 50 × 10 = 500 N

<h3>Frictional force (Fբ) =?</h3>

Fբ = μN

Fբ = 0.15 × 500

Next, we shall determine the net force acting on the crate

Frictional force (Fբ) = 75 N

Force (F) = 100 N

<h3>Net force (Fₙ) =?</h3>

Fₙ = F – Fբ

Fₙ = 100 – 75

Finally, we shall determine the acceleration of the crate

Mass (m) = 50 Kg

Net force (Fₙ) = 25 N

<h3>Acceleration (a) =?</h3>

a = Fₙ / m

a = 25 / 50

Therefore, the acceleration of the crate is 0.5 m/s²

Learn more on friction: brainly.com/question/364384

8 0

3 years ago