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Amanda [17]
3 years ago
13

What was the name of the voyages taken by Zheng he during the Ming dynasty on behalf of China

Physics
1 answer:
telo118 [61]3 years ago
6 0

Answer:

Ming treasure voyages

Explanation:

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An aluminum bar 600mm long, with diameter 40mm long has a hole drilled in the center of the bar.The hole is 30mm in diameter and
Svetradugi [14.3K]

Answer:

Total contraction on the Bar  = 1.22786 mm

Explanation:

Given that:

Total Length for aluminum bar = 600 mm  

Diameter for aluminum bar  = 40 mm

Hole diameter  = 30 mm

Hole length = 100 mm

elasticity for the aluminum is 85GN/m² = 85 × 10³ N/mm²

compressive load P = 180 KN = 180  × 10³ N

Calculate the total contraction on the bar = ???

The relation used in  calculating the contraction on the bar is:

\delta L = \dfrac{P *L }{A*E}

The relation used in  calculating the total contraction on the bar can be expressed as :

Total contraction in the Bar = (contraction in part of bar without hole + contraction in part of bar with hole)

i.e

Total contraction on the Bar = \dfrac{P *L_1 }{A_1*E} +  \dfrac{P *L_2 }{A_2 *E}

Let's find the area of cross section without the hole and with the hole

Area of cross section without the hole is :

Using A = πd²/4

A = π (40)²/4

A = 1256.64 mm²

Area of cross section with the hole is :

A = π (40²-30²)/4

A = 549.78 mm²

Total contraction on the Bar = \dfrac{P *L_1 }{A_1*E} +  \dfrac{P *L_2 }{A_2 *E}

Total contraction on the Bar  = \dfrac{180 *10^3 \N  }{85*10^3 \ N/mm^2} [\dfrac{500}{1256.64}+ \dfrac{100}{549.78}]

Total contraction on the Bar  = 2.117( 0.398 + 0.182)

Total contraction on the Bar  = 2.117*(0.58)

Total contraction on the Bar  = 1.22786 mm

5 0
3 years ago
10 POINTS AND BRAINLIEST!!!!
Maurinko [17]
The answer is earth.
7 0
3 years ago
Read 2 more answers
A line of dominos is knocked down. Which explanation is true?
Llana [10]

B: an increase in acceleration caused an increase in force.

This is based on the concept of force on an object.

Now, formula for force is commonly known as;

Force = mass × acceleration

Now, mass and acceleration are the input values that make the output which is the Force to either increase or decrease.

  • Now, for the line of dominoes to fall, it means that the force was so overwhelming that the dominoes couldn't resist it.

Now, this output which is the force became so much as a result of the increase in acceleration of the motion that triggered its movement.

Moreover, the force is directly proportional to the acceleration!

Thus, we can say that an increase in acceleration caused an increase in force.

Read more at; brainly.in/question/25954363

4 0
3 years ago
Read 2 more answers
To move a heavy object, like a refrigerator what could be used to help decrease the frictional force?
Olenka [21]

Answer:

A. Remove everything in the refrigerator to lighten the load.

B. Put a lubricant between the surface of the object and the floor

C. Use round objects, like pencils , to decrease the friction and push the refrigerator over the pencils more easily

Explanation:

Force of friction is a resistance force which acts between two surfaces which are in relative motion. Friction is both boon and bane. Due to friction, we are able to sit, walk etc but also, due to friction there is dissipation of energy. Friction can be reduced by applying lubricants, reducing contact area, reducing the load.

F = μN where N is the normal force which depends on the mass.

Thus, by reducing the load, force of friction can be reduced. Round objects like wheels can also be used. By this the contact area reduces.

8 0
3 years ago
An instrument is defective for all of the following conditions EXCEPT:_______
NARA [144]

Answer:

I believe its C

6 0
3 years ago
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