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3 years ago

After a 65 newton weight has fallen freely from rest a vertical distance of 5.3 meters, the kinetic energy of the weight is

Engineering

1 answer:

inysia [295]3 years ago

3 0

Answer:

The kinetic energy of the weight is 344.5 J

Explanation:

Given that:

Force = F = 65 newton

distance = d = 5.3 meters

We have to find change in kinetic energy ΔK.E

Now we know that, initially kinetic energy was 0 So the formula we use will be:

Work done = Change in kinetic energy

Mathematically,

W = ΔK.E

As we know W = F . d and ΔK.E = K.E(final) - K.E(initial)

So by putting values:

F . d = K.E(final) - K.E(initial)

F . d = K.E(final)

As K.E(initial) is 0 so by putting values of F and d

(65)* (5.3) = K.E(final)

344.5 J = K.E(final)

So the change in K.E will also be 344.5 J

i hope it will help you!

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insens350 [35]

<u>Explanation:</u>

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$W_{f}=\gamma(L)(B)(D)$

Where $W_{f}$ is the weight of footing, γ is the unit weight of concrete, L is the length of footing is the width of footing, and D is the depth of footing

Substitute $2 m \text { for } L, 1.5 m \text { for } B, 0.5 m \text { for } D \text { and } 23.6 kN / m ^{3}$ for γ in the equation

$\begin{aligned}W_{f} &=\left(23.6 kN / m ^{3}\right)(2 m )(1.5 m )(0.5 m ) \\&=35.4 kN\end{aligned}$

Therefore, the weight of the footing is 35.4 kN

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$\sigma_{z p}^{\prime}=\gamma(D+B)-u$

Here, $\sigma_{z^{p}}^{\prime}$ is initial vertical stress at a depth below ground surface γ is the unit weight of soil, D is depth and u is pore water pressure.

Substitute $18 kN / m ^{3} \text { for } \gamma, 1.5 m \text { for } B, 0.5 m \text { for } D \text { and } 0$ for u in the equation

$\begin{aligned}\sigma_{z p}^{\prime} &=\left(18 kN / m ^{3}\right)(1.5+0.5) m -0 \\&=36 kPa\end{aligned}$

Therefore, the initial vertical stress is 36 kPa

Determine the vertical effective stress.

$\sigma_{z D}^{\prime}=\gamma D$

Here, $\sigma_{z^{p}}^{\prime}$ is initial vertical stress at a depth below ground surface γ is the unit weight of soil, D is depth and u is pore water pressure.

Substitute $18 kN / m ^{3}\) for $\gamma, 0.5 m$ for $D$ and 0 for \(u$ in the equation.

$\begin{aligned}\sigma_{z b}^{\prime} &=\left(18 kN / m ^{3}\right)(0.5 m )-0 \\&=9 kPa\end{aligned}$

Therefore, the vertical stress at a depth below the ground surface is

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Here $I_{e p}$ is the influence factor at the midpoint of soil layer $\sigma_{z^{p}}^{\prime}$ is initial vertical stress, $\sigma_{z^{p}}^{\prime}$ is vertical effective stress, and $Q$ is bearing pressure

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