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3 years ago

Select the correct answer.

Physics

2 answers:

ivann1987 [24]3 years ago

6 0

Answer:

We’ll see the bell move, but we won’t hear it ring.

Explanation:

Sound waves need a medium to travel and cannot travel in vaccuum

Stels [109]3 years ago

5 0

Answer:

An electric bell is placed inside a transparent glass jar. The bell can be turned on and off using a switch on the outside of the jar. A vacuum is created inside the jar by sucking out the air. Then the bell is rung using the switch. What will we see and hear?

We’ll see the bell move, but we won’t hear it ring.

We won’t see the bell move, but we’ll hear it ring.

We’ll see the bell move and hear it ring.

We won’t see the bell move or hear it ring.

We’ll see the sound waves exit the vacuum pump.

Explanation:

so, the answer to the question is

We'll see the bell move, but we won’t hear it ring.

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If you apply 100.0 N of force to lift an object with a single, fixed pulley, then what is the resistive force?

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If you apply 100.0 N of force to lift an object with a single, fixed pulley, then the resistive force is also equivalent to 100 Newtons of force. Since the weight of the object was not mentioned, it is assumed that it has already been taken into account in the 100 N value of force. This follows Newton's law of motion of equal action and reaction.

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3 years ago

Which image shows the correct way of lining up vectors to add them

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Answer:

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Explanation:

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1 year ago

How does gravity affect the velocity of falling objects?

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3 years ago

A tree falls in a forest. How many years must pass before the 14C activity in 1.03 g of the tree's carbon drops to 1.02 decay pe

Illusion [34]

Answer:

t = 5.59x10⁴ y

Explanation:

To calculate the time for the ¹⁴C drops to 1.02 decays/h, we need to use the next equation:

$A_{t} = A_{0}\cdot e^{- \lambda t}$ (1)

where $A_{t}$ : is the number of decays with time, A₀: is the initial activity, λ: is the decay constant and t: is the time.

To find A₀ we can use the following equation:

$A_{0} = N_{0} \lambda$ (2)

where N₀: is the initial number of particles of ¹⁴C in the 1.03g of the trees carbon

From equation (2), the N₀ of the ¹⁴C in the trees carbon can be calculated as follows:

$N_{0} = \frac{m_{T} \cdot N_{A} \cdot abundance}{m_{^{12}C}}$

where $m_{T}$ : is the tree's carbon mass, $N_{A}$ : is the Avogadro's number and $m_{^{12}C}$ : is the ¹²C mass.

$N_{0} = \frac{1.03g \cdot 6.022\cdot 10^{23} \cdot 1.3\cdot 10^{-12}}{12} = 6.72 \cdot 10^{10} atoms ^{14}C$

Similarly, from equation (2) λ is:

$\lambda = \frac{Ln(2)}{t_{1/2}}$

where t 1/2: is the half-life of ¹⁴C= 5700 years

$\lambda = \frac{Ln(2)}{5700y} = 1.22 \cdot 10^{-4} y^{-1}$

So, the initial activity A₀ is:

$A_{0} = 6.72 \cdot 10^{10} \cdot 1.22 \cdot 10^{-4} = 8.20 \cdot 10^{6} decays/y$

Finally, we can calculate the time from equation (1):

$t = - \frac{Ln(A_{t}/A_{0})}{\lambda} = - \frac {Ln(\frac{1.02decays \cdot 24h \cdot 365d}{1h\cdot 1d \cdot 1y \cdot 8.20 \cdot 10^{6} decays/y})}{1.22 \cdot 10^{-4} y^{-1}} = 5.59 \cdot 10^{4} y$

I hope it helps you!

4 0

3 years ago

Choose the correct explanation of whether the discovery should be considered reasonable or surprising.

earnstyle [38]

Answer: a. This would be exciting, but not surprising. Heat from Martian volcanoes may well be enough to melt water under the Mars' surface.

Explanation: It was recently observed by a team of geological researchers that there exist some activity at the crust of the planet mars. This activity are volcanic in nature and estimated to be about 10kilometers large. Also this volcanic eruptions in the planet mars core are described as among the largest in our solar system. Therefore it won't be a surprise that Heat from Martian volcanoes may well be enough to melt water under the Mars' surface.

6 0

3 years ago