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adell [148]
3 years ago
14

Based on The MOHS hardness Scale, which mineral could be scratched by a penny but not by a fingernail

Physics
1 answer:
melomori [17]3 years ago
6 0

The correct answer is B. Calcite

Explanation:

Mohs hardness scale indicates the hardness of minerals using a scale from 1 to 10 as well as defining the objects or tools that can be used to scratch the minerals. These two features of minerals are shown in the table of the image. About this, it is shown gypsum and talc can be scratched by just a fingernail, considering minerals with a hardness of 2.5 or below can be scratched by a fingernail. In the case of calcite that has a hardness of 3, this cannot be scratched by a fingernail, but it can be scratched by a penny, which works for minerals with a hardness of 3.5 or below. Thus, the correct answer is Calcite.

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Gwar [14]

(a) The stress in the post is 1,568,000 N/m²

(b) The strain in the post is  7.61 x 10⁻⁶  

(c) The change in the post’s length when the load is applied is 1.9 x 10⁻⁵ m.

<h3>Area of the steel post</h3>

A = πd²/4

where;

d is the diameter

A = π(0.25²)/4 = 0.05 m²

<h3>Stress on the steel post</h3>

σ = F/A

σ = mg/A

where;

  • m is mass supported by the steel
  • g is acceleration due to gravity
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σ = (8000 x 9.8)/(0.05)

σ = 1,568,000 N/m²

<h3>Strain of the post</h3>

E = stress / strain

where;

  • E is Young's modulus of steel = 206 Gpa

strain = stress/E

strain = (1,568,000) / (206 x 10⁹)

strain = 7.61 x 10⁻⁶

<h3>Change in length of the steel post</h3>

strain = ΔL/L

where;

  • ΔL is change in length
  • L is original length

ΔL = 7.61 x 10⁻⁶ x 2.5

ΔL = 1.9 x 10⁻⁵ m

Learn more about Young's modulus of steel here: brainly.com/question/14772333

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7 0
1 year ago
A bullet of mass 0.01 kg is fired in to a sand bas of mass 0.49 kg from a tree. The Sand bag with the bullet embedded in to it s
makvit [3.9K]

Since the bag was at rest, its initial momentum is zero. The velocity of the ball before collision is 500 ms-1.

<h3>Linear momentum</h3>

The term momentum in physics refers the product of mass and velocity. If we know mass of the object and its velocity, then we calculate the momentum.

Momentum before collision for the bullet = 0.01 kg × v

Momentum before collision for the bag = 0

Momentum after collision for the bag and bullet = (0.01 kg  +  0.49 kg) 10 = 5 Kgms-1

The velocity of the bullet before collision =  0.01 kg × v + 0 =  5 Kgms-1

v = 5 Kgms-1/0.01 kg

v = 500 ms-1

Learn more about momentum: brainly.com/question/904448

8 0
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iogann1982 [59]

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Explanation:

Given:

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