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WITCHER [35]
2 years ago
11

. What is the atomic number for calcium?

Physics
1 answer:
zheka24 [161]2 years ago
8 0
20 is the atomic number for Calcium.
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Ball is dropped from the height H the total distance covered in last second of its motion is equal to distance covered in first
Alik [6]

\rm{\gray{\underline{\underline{\blue{GIVEN:-}}}}}

  • A ball is dropped from a height = H

  • The total distance covered in last second of its motion is equal to the distance covered in first 3 second .

\rm{\gray{\underline{\underline{\blue{TO\:FIND:-}}}}}

  • The height of the journey .

\rm{\gray{\underline{\underline{\blue{SOLUTION:-}}}}}

We have know that,

\green\bigstar\:\rm{\gray{\overbrace{\underbrace{\red{S\:=\:ut\:+\:\dfrac{1}{2}\:at^2\:}}}}}

Where,

  • S = Distance .

  • u = initial velocity = 0m/s

  • t = time = 3s

  • a = acceleration

[Note :- Here, acceleration is ‛acceleration due to gravity’ .]

  • a = 10m/s^2

=> S = 1/2 × 10 × (3)^2

=> S = 5 × 9

=> S = <u>4</u><u>5</u><u>m</u> -----(1)

✒ If the ball takes ‛n’ second to fall the ground, then distance covered in nth second is,

\green\bigstar\:\rm{\gray{\overbrace{\underbrace{\red{S_n\:=\:u\:+\:\dfrac{g}{2}\:(2n\:-\:1)\:}}}}}

=> Sn = 0 + 10/2 (2 × n - 1)

=> Sn = 5 (2n - 1)

=> Sn = 10n - 5 -----(2)

Therefore,

  • 10n - 5 = 45

=> 10n = 45 + 5

=> n = 50/10

=> n = <u>5</u>

Now put the value of ‛n = 5’ in equation(2), we get

=> Sn = 10 × 5 - 5

=> Sn = 50 - 5

=> <u>Sn</u><u> </u><u>=</u><u> </u><u>4</u><u>5</u><u>m</u>

\rm{\pink{\therefore}} The height of the journey is “ <u>4</u><u>5</u><u>m</u> ” .

7 0
3 years ago
Does a material have less mass when it has contracted?
Lyrx [107]

Answer:No

Explanation:The amount of mass is the amount of matter in an object if it is contracted the mass stays the same, it is just more dense

8 0
3 years ago
Lighting a match results in light and heat. Since energy was not created by the match, what transformation took place?
Yuki888 [10]
Chemical energy stored in the compounds caked on the head of the match, and later the
chemical energy stored in the wood, was released in the form of heat and light when the
chemical compounds got hot enough.
3 0
3 years ago
One way to improve food security is to avoid food spoilage. Identify the correct ways that Devon reduced food spoilage in the pa
quester [9]

The correct answer would be "He brought one serving to his neighbor's house, and stored the other two servings in the refrigerator. Devon ate one more serving or spaghetti the following day."

3 0
3 years ago
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A car enters a horizontal, curved roadbed of radius 50 m. the coefficient of static friction between the tires and the roadbed i
UkoKoshka [18]
Previous results tell us the speed (v) is given in terms of the coefficient of friction (k) and the radius of the curve (r) as
  v = √(kgr)
  v = √(0.20·9.8 m/s²·50 m)
  = 7√2 m/s ≈ 9.90 m/s
6 0
2 years ago
Read 2 more answers
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