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3 years ago

10

In a crash test, a 1000 kg automobile moving at 10 m/s crashes into a brick wall. How much energy goes into demolishing and warm

ing the wall and the auto?

1 answer:

marishachu [46]3 years ago

8 0

Answer:

Explanation:

Given

mass of automobile $m=1000\ kg$

velocity of automobile $v=10\ m/s$

If the automobile crashes into the brick wall then it's kinetic energy is converted into thermal and demolishing energy to wall.

Car completely stops as it crashes into the wall so Energy converted into demolition and thermal energy

$E=\frac{1}{2}mv^2$

$E=\frac{1}{2}\times 1000\times (10)^2$

$E=50\ kJ$

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Ghella [55]

Answer:

f = - 0.143 m = - 14.3 cm

Explanation:

First, we will calculate the power of the combination of lenses:

P = P₁ + P₂

where,

P = Power of Combination = ?

P₁ = Power of first lens = - 5D

P₂ = Power of second lens = - 2D

Therefore,

P = - 5D - 2D

P = - 7D

Now, the focal length can be given as:

$f = \frac{1}{P} \\\\f = \frac{1}{-\ 7\ D} \\\\$

<u>f = - 0.143 m = - 14.3 cm</u>

Negative focal length indicates that combination will act as diverging lens.

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A 0.40 kg object is attached to a spring with force constant 157 N/m so that the object is allowed to move on a horizontal frict

nirvana33 [79]

Answer:

Part a)

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Part b)

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Explanation:

Part a)

Force on the object due to spring force is given as

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here we know that

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$F = 26.7 N$

Part b)

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$a = \frac{26.7}{0.40}$

$a = 66.7 m/s^2$

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3 years ago

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Explanation:

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$\dfrac{dy}{dt}=0.8\times \dfrac{dx}{dt}-0.8x\times \dfrac{dx}{dt}$

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