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3 years ago

What are some similarities and differences between elements, compounds, and mixtures?

2 answers:

4 0

The similarities between compounds and mixtures are that they are both made up of two or more elements and that they could both be separated and then mixed with different elements to make a new mixture and compound.

VladimirAG [237]3 years ago

3 0

A mixture is made from two or more substances that are chemically different and are not chemically joined.A compound is a substance formed when two or more elements chemically react with each other to form chemical bonds between their atoms.

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In a 5000 m race, the athletes run 12 1/2 laps; each lap is 400 m.Kara runs the race at a constant pace and finishes in 17.9 min

Ksju [112]

Answer:

No. of laps of Hannah are 7 (approx).

Solution:

According to the question:

The total distance to be covered, D = 5000 m

The distance for each lap, x = 400 m

Time taken by Kara, $t_{K} = 17.9 min = 17.9\times 60 = 1074 s$

Time taken by Hannah, $t_{H} = 15.3 min = 15.3\times 60 = 918 s$

Now, the speed of Kara and Hannah can be calculated respectively as:

$v_{K} = \frac{D}{t_{K}} = \frac{5000}{1074} = 4.65 m/s$

$v_{H} = \frac{D}{t_{H}} = \frac{5000}{918} = 5.45 m/s$

Time taken in each lap is given by:

$(v_{H} - v_{K})t = x$

$(5.45 - 4.65)\times t = 400$

$t = \frac{400}{0.8}$

t = 500 s

So, Distance covered by Hannah in 't' sec is given by:

$d_{H} = v_{H}\times t$

$d_{H} = 5.45\times 500 = 2725 m$

No. of laps taken by Hannah when she passes Kara:

$n_{H} = \frac{d_{H}}{x}$

$n_{H} = \frac{2725}{400} = 6.8$ ≈ 7 laps

3 0

3 years ago

The speed of light is 3.0 x 108 m/s. How far does light travel in one day? Remember that you should first convert the day into s

Anna35 [415]

Answer:

$2.59\times 10^{13}\ m$

Explanation:

The speed of light is 3.0 x 10⁸ m/s

We need to find the distance traveled by it in one day.

1 day = 24 hours

1 day = 24 × 3600 seconds

= 86400 s

Now, using the formula of speed to find the distance covered as follows :

$d=v\times t$

Putting all the values, we get :

$d=3\times 10^8\ m/s\times 86400\ s\\\\d=2.59\times 10^{13}\ m$

Hence, light will cover $2.59\times 10^{13}\ m$ of distance in one day.

6 0

3 years ago

Determined to test the law of gravity for himself, a student walks off a skyscraper 180 m high, stopwatch in hand, and starts hi

Sati [7]

Answer:

a) v₀ = - 164.62 m / s , c) y = 122.5 m

Explanation:

We can solve this exercise using the free fall kinematic relations.

We put our reference system on the floor, so the height of the skyscraper is y₀ = 180m and the floor level is y = 0 m

For the boy

y = y₀ + v₀ t - ½ g t²

with free fall its initial speed is zero

y = ½ g t2

For superman

y = y₀ + v₀ (t-5) - ½ g (t-5)²

how superman grabs the lot just before hitting the ground

we look for the time it takes the boy down

t = √ (2 y₀ / g)

t = √ (2 180 / 9,8)

t = 6.06 s

in the equation for superman, we clear the volume and calculate

v₀ (t-5) = -y₀ + ½ g (t-5)²

v₀ (6.06 -5) = -180 + ½ 9.8 (6.06 -5)²

v₀ 1.06 = -174.49

v₀ = - 174.49 / 1.06

v₀ = - 164.62 m / s

the negative sign indicates that the initial speed is down

b) to graph the position of the two we use the table

t (s) Y_boy (m) Y_superman (m)

0 180 180

1 175.1 180

5 57.5 180

6 3.6 10.18

see attachment for the two curves

c) calculate the height that falls a lot in the 5 seconds (t = 5)

y = -1/2 g t²

y = ½ 9.8 5²

y = 122.5 m

for this height superman has not yet left the skyscraper, so the boy hits the ground

8 0

4 years ago

A specimen of aluminum having a rectangular cross section 9.5 mm × 12.9 mm (0.3740 in. × 0.5079 in.) is pulled in tension with 3

ryzh [129]

Answer:

The resultant strain in the aluminum specimen is $4.14 \times {10^{ - 3}}$

Explanation:

Given that,

Dimension of specimen of aluminium, 9.5 mm × 12.9 mm

Area of cross section of aluminium specimen,

$A=9.5\times 12.9=123.84\times 10^{-6}\ mm^2A=122.55\times 10^{-6}\ m^2$

Tension acting on object, T = 35000 N

The elastic modulus for aluminum is, $E=69\ GPa=69\times 10^9\ Pa$

The stress acting on material is proportional to the strain. Its formula is given by :

$\epsilon=\dfrac{\sigma}{E}$

$\sigma$ is the stress

$\epsilon=\dfrac{F}{EA}\\\epsilon=\dfrac{35000}{69\times 10^9\times 122.5\times 10^{-6}}\\\epsilon=4.14\times 10^{-3}$

Thus, The resultant strain in the aluminum specimen is $4.14 \times {10^{ - 3}}$

5 0

4 years ago

Read 2 more answers

The range is the horizontal distance from the cannon when the pumpkin hits the ground. This distance is given by the product of

jarptica [38.1K]

The answer is 45 degrees. I am not doing a field experiment for you that involves a cannon and a day's work, for 5 points.

3 0

3 years ago