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Anvisha [2.4K]
3 years ago
11

A student is studying calcium, a highly reactive element that humans need for strong bones. Which characteristic of calcium is m

ost closely related to its chemical reactivity?
A The 20 protons in each atom of calcium B The density of calcium, which is 1.54 g/cm3
C The atomic mass of calcium, which is 40.078 amu D The 2 valence electrons in each atom of calcium
Physics
1 answer:
dezoksy [38]3 years ago
8 0

Answer:d

Explanation:

I took the quiz and I got that question right :)

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Your bike starts with an initial velocity of 1 m/s and you accelerate to 4 m/s in 6 seconds. How far did you travel while accele
garri49 [273]

Answer:

78 m

Explanation:

Initial v = 1 m/s

a = 4 m/s²

t = 6s

x = v_{i} t + \frac{1}{2}at^{2} \\x = (1)(6) + \frac{1}{2} (4)(6)^{2} \\x = 6 + 72\\x = 78

5 0
3 years ago
If a steady-state heat transfer rate of 3 kW is conducted through a section of insulating material 1.0 m2 in cross section and 2
kaheart [24]

Answer:

\Delta T = \frac{3000 W *0.025 m}{1 m^2 (0.2 \frac{W}{mK})}= 375 K

So then the difference of temperature across the material would be \Delta T = 375 K

Explanation:

For this case we can use the Fourier Law of heat conduction given by the following equation:

Q = -kA \frac{\Delta T}{\Delta x}   (1)

Where k = thermal conductivity = 0.2 W/ mK

A= 1m^2 represent the cross sectional area

Q= 3KW represent the rate of heat transfer

\Delta T is the temperature of difference that we want to find

\Delta x=2.5 cm =0.025 m represent the thickness of the material

If we solve \Delta T in absolute value from the equation (1) we got:

\Delta T =\frac{Q \Delta x}{Ak}

First we convert 3KW to W and we got:

Q= 3 KW* \frac{1000W}{1 Kw}= 3000 W

And we have everything to replace and we got:

\Delta T = \frac{3000 W *0.025 m}{1 m^2 (0.2 \frac{W}{mK})}= 375 K

So then the difference of temperature across the material would be \Delta T = 375 K

5 0
4 years ago
What is done when an object is moved by a force
Flauer [41]

1). The object winds up in a different location.

2). Work is done.

7 0
4 years ago
Which statement about the physical change of liquid water boiling into steam is true? The heat added represents an energy change
Colt1911 [192]

Answer:

The heat added represents an energy change.

Explanation:

6 0
3 years ago
Read 2 more answers
A pendulum takes 6.0 seconds to swing through 5 complete cycles. What is the period of the pendulum?
photoshop1234 [79]
When you look at this, you might not be sure which way to divide ...
Should you divide  6 by 5  or  5 by 6 ?

Here's a case where you can use your units to decide.

The question wants to know the 'period'.  That's a length of time,
so the answer needs to have units of time.

If you divide 'cycles' be 'time', you'll get  'cycles/second'.
That's Hz.  It's frequency, not time.

If you divide 'time' by 'cycles', you'll get 'seconds/cycle'.
That's time, and it's exactly the definition of 'period'.

            Period  =  (6 seconds) / (5 cycles)

                         =    (6 / 5)  seconds/cycle

                         =     1.2  seconds 
6 0
3 years ago
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