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alexandr402 [8]
3 years ago
6

If the half- life of a sample of a radioactive substance is 30 seconds, how much would be left after 60 seconds ?

Physics
1 answer:
n200080 [17]3 years ago
5 0
After 30 seconds half is left.  After 30 more seconds, half of that much will be left (25%) or 1/4 of the original amount
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Ian walks 2 km to his best friend's house, then walks 0.5 km to the library. He then makes a 2.5 km walk home. The entire walk t
earnstyle [38]

Average speed = (total distance covered) / (time to cover the distance)

Ian's total distance covered = (2km + 0.5km + 2.5km) = 5 km.

His time to cover the distance = 3 hours.

Average speed = (5 km) / (3 hrs)

Average speed = (5/3) (km/hr)

<em>Average speed = 1.67 km/hr</em>

5 0
3 years ago
Convert 15 litre into cubic metre​
atroni [7]

Answer:

0.015m^3

Explanation:

1 m^3 = 1000 liters

x m^3 = 15 liters

Cross multiply

xm^3 x 1000 l = 15 l

Divide both sides by 1000

xm^3 x1000/1000 = 15/1000

xm^3 = 0.015m^3

Therefore 15 liter = 0.015m^3

5 0
3 years ago
1. Determine the magnitude of two equal but opposite charges if they attract one another with a force of 0.7N when at distance o
adell [148]

Answer:

q = 2.65 10⁻⁶ C

Explanation:

For this exercise we use Coulomb's law

        F =k \frac{q_1q_2}{r^2}

In this case they indicate that the load is of equal magnitude

       q₁ = q₂ = q

the force is attractive because the signs of the charges are opposite

       F = k \ \frac{q^2}{r^2}

       q = \sqrt{\frac{F \ r^2}{k} }

we calculate

        q = \sqrt{\frac{0.7 \ 0.3^2 }{9 \ 10^9}  }

        q = \sqrt{7 \ 10^{-12} }Ra 7 10-12

        q = 2.65 10⁻⁶ C

7 0
3 years ago
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4 years ago
1. Which word or phrase best describes entropy?
Mama L [17]
The answer to this question is:

D) Disorder
7 0
4 years ago
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