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4 years ago

Cotton is lighter than iron .why?

1 answer:

3 0

Cotton is significantly less dense than iron. Therefore if you have equal volume samples of cotton and iron, the iron sample will weigh more than the cotton sample.

A substance's relative density is the ratio of its density to that of liquid water. You are taking two quantities with the same unit and dividing them. This will cancel out the unit on the top and bottom, leaving you with a number that has no unit.

Inflating a balloon puts it under an awful lot of pressure. The material must remain pretty durable throughout in order to sustain that much stress. Any weak spots inside the balloon will eventually give way; the balloon will then rip and pop.

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A radioactive isotope has a half-life of 5,000 years. A rock originally contained 16 grams of radioactive isotope, and now conta

mixas84 [53]

Answer:

10,000 years

Explanation:

Given that,

Half life of the radioactive isotope, $t_{\frac{1}{2}}$ = 5000 years

Initial composition, $N_0$ = 16 grams

Final composition, $N$ = 4 grams

We know that,

$N=N_0\times (\dfrac{1}{2})^\frac{t}{t_\frac{1}{2}}}\\\\4=16(0.5)^\frac{t}{5000}}\\\\\dfrac{4}{16}=(0.5)^{\frac{t}{5000}}\\\\0.25=(0.5)^\frac{t}{5000}\\\\0.5^2=(0.5)^\frac{t}{5000}\\\\2=\dfrac{t}{5000}\\\\t=2\times 5000\\\\t=10000\ yrs$

Therefore, the age of the rock is 10,000 years.

6 0

3 years ago

Help pleas!!!!

grin007 [14]

It will spread faster in the hot water! It would spread slower in cold water

6 0

3 years ago

Read 2 more answers

The current supplied by a battery slowly decreases as the battery runs down. Suppose that the current as a function of time is:

ludmilkaskok [199]

Answer: 8.1 x 10^24

Explanation:

I(t) = (0.6 A) e^(-t/6 hr)

I'll leave out units for neatness: I(t) = 0.6e^(-t/6)

If t is in seconds then since 1hr = 3600s: I(t) = 0.6e^(-t/(6 x 3600) ).

For neatness let k = 1/(6x3600) = 4.63x10^-5, then:

I(t) = 0.6e^(-kt)

Providing t is in seconds, total charge Q in coulombs is

Q= ∫ I(t).dt evaluated from t=0 to t=∞.

Q = ∫(0.6e^(-kt)

= (0.6/-k)e^(-kt) evaluated from t=0 to t=∞.

= -(0.6/k)[e^-∞ - e^-0]

= -0.6/k[0 - 1]

= 0.6/k

= 0.6/(4.63x10^-5)

= 12958 C

Since the magnitude of the charge on an electron = 1.6x10⁻¹⁹ C, the number of electrons is 12958/(1.6x10^-19) = 8.1x10^24 to two significant figures.

5 0

4 years ago

Why are identical bulbs arranged in a series circuit with a battery less bright than those arranged in a parallel circuit with t

tatuchka [14]

Explanation:

Resistors connected in series obey the following equation:

$R_{\rm eq} = R_1 + R_2 + R_3 + ...$

Resistors connected in parallel obey the following equation:

$\frac{1}{R_{\rm eq}} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} + ...$

The total current of the circuit will obey the Ohm's Law: V = IR. And the current will be divided across the resistors (bulbs) depending on their resistances. So, if a bulb has a higher resistance, then its current will be lesser, and it will be less bright. If a bulb has a lower resistance, then its current will be higher, and it will be brighter.

According to the above resistances connected in series and parallel, clearly, the resistances (bulbs) connected in series will have more resistance in total, and therefore less current will flow across them, and they will be less bright.

6 0

3 years ago

Need help with this question

lakkis [162]

Answer:

1.39m

Explanation:

5 0

2 years ago

Read 2 more answers