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2 years ago

Please help

Physics

2 answers:

vladimir2022 [97]2 years ago

5 0

Answer:

true true false true false

Greeley [361]2 years ago

4 0

Answer:

1)true

2)true

3)false

4)false

5)true

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How much heat is absorbed by 60 kg of copper (c=385 J/kg K) when it is heated from 10C to 60 C?

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The amount of heat absorbed by the metal copper can be directly solved using the formula:

Q = m c ΔT

Q = 60 kg * 385 J / kg K * (60 – 10) K

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4 years ago

When vibrational motion in an object increases, which is a true statement?

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When vibrational motion in an object increases, the statement that is true is that the kinetic energy temperature and thermal energy increases. The correct option among all the options that are given in the question is the second option or option "B". I hope the answer comes to your help.

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3 years ago

A 23.0 kg child plays on a swing having support ropes that are 2.10 m long. A friend pulls her back until the ropes are 45.0 deg

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Answer:

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b.3.486m/s

c.zero

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Potential energy during release is calculated as: $PE=mgh$

#Find vertical difference of when the swing is at rest (2.1m) and when the child is pulled back.

Find the height when the child is pulled back:

$cos 45\textdegree=y/2.10\\\\y=1.48m$

#therefore,vertical difference is 2.1m-1.48m=0.62m

$\therefore PE=mgh\\\ \ =23.0kg\times 9.8m/s^2\times 0.62m\\\ \ =139.748J$

#Hence the potential energy during release is 139.748J

b. From a, above, we have PE=139.748J, M=23.0kg.

At the bottom, all the PE will be transferred into KE. Potential energy is calculated as:

$KE=0.5mv^2\\\\mv^2=2KE\\\\v=\sqrt{2KE/m}\\\\v=\sqrt{2\times 139.748J/23.0}\\\\v=3.486m/s$

#Hence the velocity at the bottom of the swing is 3.486m/s

c. Work is calculated as the product of force by distance.

From a, b above we have mass as 23.0kg .

-since the distance of the ropes remained constant the change in distance is zero:

$W=mgd\\=23.0\times 9.8m/s^2\times 0\\=0$

Therefore the work in the ropes is 0,zero.

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3 years ago

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Answer:

The correct answer is Joseph Stalin.

Explanation:

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