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3 years ago

12

You place a book on top of a spring and push down, compressing the spring by 10 cm. When you let go of the book, it is pushed up

by the spring. Which statement describes what happens to the energy of the spring-book-system?

2 answers:

enot [183]3 years ago

4 0

At First, there is chemical Energy( in your muscels) which is Used to Push down the spring. This Energy becomes the Energy of the spring, which increases until you stop pushing. If you Put your hand away, the Energy of the spring will become kinetic energ. This Energy is at the highest Level the Moment the book ist Leaving the spring. Afterwards, the kinetic Energy decreases while the Gravitational Potential Energy increases.

DochEvi [55]3 years ago

3 0

Answer: The gravitational potential energy of the system increases.

Explanation:

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Licemer1 [7]

Answer:

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v1 = 9*10^4 m/s

From conservation of energy

K1 +U1 = K2 +U2

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0.5*(9*10^4)^2 - (6.67*10^-11*1.98*10^30/(5*10^10)) = 0.5v2^2 - (6.67*10^-11*1.98*10^30/(6*10^12))

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3 years ago

Sean, an astronaut stands on the edge of a lunar crater and throws a Frisbeeâ„˘ horizontally with a velocity of 5.00 m/s. With n

motikmotik

Answer:

48.55mm

Explanation:

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3 years ago

viktelen [127]

Answer: D(t) = $8.e^{-0.4t}.cos(\frac{\pi }{6}.t )$

Explanation: A harmonic motion of a spring can be modeled by a sinusoidal function, which, in general, is of the form:

y = $a.sin(\omega.t)$ or y = $a.cos(\omega.t)$

where:

|a| is initil displacement

$\frac{2.\pi}{\omega}$ is period

For a Damped Harmonic Motion, i.e., when the spring doesn't bounce up and down forever, equations for displacement is:

$y=a.e^{-ct}.cos(\omega.t)$ or $y=a.e^{-ct}.sin(\omega.t)$

For this question in particular, initial displacement is maximum at 8cm, so it is used the cosine function:

$y=a.e^{-ct}.cos(\omega.t)$

period = $\frac{2.\pi}{\omega}$

12 = $\frac{2.\pi}{\omega}$

ω = $\frac{\pi}{6}$

Replacing values:

$D(t)=8.e^{-0.4t}.cos(\frac{\pi}{6} .t)$

The equation of displacement, D(t), of a spring with damping factor is $D(t)=8.e^{-0.4t}.cos(\frac{\pi}{6} .t)$ .

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3 years ago

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Travka [436]

Answer:

$0.62\:\mathrm{s}$

Explanation:

Since the universal SI unit for velocity is meters/second, let's convert ft/s to m/s:

$10\:\mathrm{ft/s}=3.048\:\mathrm{m/s}$

We can use the following kinematics equation to solve this question:

$v_f=v_i+at$

What we know:

The initial velocity, $v_i$ , is $3.048\:\mathrm{m/s}$

(physics concept) The final velocity must be equal in magnitude but opposite in direction to the initial velocity ( $v_f=-3.048\:\mathrm{m/s}$ )
Acceleration, $a$ , is acceleration due to gravity at about $9.8\:\mathrm{m/s}$

Solving for $t$ :

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3 years ago

Two vehicles approach an intersection: a truck moving eastbound at 16.0 m/s and an SUV moving southbound at 20.0 m/s. Suppose th

mario62 [17]

Answer:25.61 m/s

Explanation:

Given

truck is moving eastbound with a velocity of 16 m/s

Velocity of truck $v_t=16\hat{i}$

SUV is moving south with a velocity of 20 m/s

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$v_{ts}=v_{t}-v_s$

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