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3 years ago

A) the unstretched length of each elastic rope is 24m. The rope obeys hookes law. The vertical distance between P and Q is 35m.

Physics

1 answer:

solong [7]3 years ago

6 0

Explanation:

a) The rope obeys Hooke's law, so:

F = k Δx

The elastic energy in the rope is:

EE = ½ k Δx²

Or, in terms of F:

EE = ½ F Δx

Use trigonometry to find the stretched length.

cos 20° = 35 / x

x = 37.25

So the displacement is:

Δx = 37.25 − 24

Δx = 13.25

The elastic energy per rope is:

EE = ½ (3.7×10⁴ N) (13.25 m)

EE = 245,000 J

There's two ropes, so the total energy is:

2EE = 490,000 J

Rounded to one significant figure, the elastic energy is 5×10⁵ J.

b) The elastic energy in the ropes is converted to gravitational energy.

EE = PE = mgh

5×10⁵ J = (1.2×10³ kg) (9.8 m/s²) h

h = 42 m

Rounded to one significant figure, the height is 40 m. So the claim is not justified.

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Read 2 more answers

The first law of thermodynamics states that ΔE= Q− W . Is this also a statement of the principle of conservation of energy? Yes,

ozzi

Answer:

Yes, the heat that flows into the system is used to change the internal energy of the gas and becomes work done by the piston.

Explanation:

First law of thermodynamics known as Law of Conservation of Energy, states that energy can neither be created nor destroyed; energy can only be transferred or changed from one form to another.

The first law of thermodynamics states that the change in internal energy of a system equals the net heat transfer into the system minus the net work done by the system. In equation form, the first law of thermodynamics.

This is the first law of thermodynamics

ΔE= Q− W

ΔE= change internal energy of the system.

Q= heat transfer into the system

And

W= work done by the system.

Rewriting the equation

ΔE= Q− W

Q=ΔE +W

Show that the heat flowing l into the system is transferred to the internal energy of the system and the work done by the piston

So the third option is correct

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3 years ago