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3 years ago

An unnamed spacecraft leaves for Venus. Which statements about the spacecrafts journey are true?

Physics

2 answers:

NNADVOKAT [17]3 years ago

7 0

Answer:

A. The weight of the spacecraft keeps changing.

D. The mass of the spacecraft remains the same.

Explanation:

alexgriva [62]3 years ago

6 0

A) The weight of the spacecraft keeps changing, because its distance from Earth is changing.

also ...

B) The mass of the spacecraft keeps changing, because it's burning fuel. If it were not firing its engines and losing fuel, then its mass wouldn't change no matter where it goes.

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When sound waves travel through a medium, the particles of the medium move parallel to the wave motion. Which type of wave displ

Karo-lina-s [1.5K]

Longitudinal waves move parallel to the wave motion.

3 0

3 years ago

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As a result of friction, the angular speed of a wheel changes with time according to dθ/dt = ω0e^−σt where ω0 and σ are constant

NNADVOKAT [17]

Hi there!

We can use the initial conditions to solve for w₀.

It is given that:

$\frac{d\theta}{dt} = w_0e^{-\sigma t}$

We are given that at t = 0, ω = 3.7 rad/sec. We can plug this into the equation:

$\omega(0)= \omega_0e^{-\sigma (0)}\\\\3.7 = \omega_0 (1)\\\\\omega_0 = \boxed{3.7 rad/sec}$

Now, we can solve for sigma using the other given condition:

$2 = 3.7e^{-\sigma (8.6)}\\\\.541 = e^{-\sigma (8.6)}\\\\ln(.541) = -\sigma (8.6)\\\\\sigma = \frac{ln(.541)}{-8.6} = \boxed{0.0714s^{-1}}$

The angular acceleration is the DERIVATIVE of the angular velocity function, so:

$\alpha(t) = \frac{d\omega}{dt} = -\sigma\omega_0e^{-\sigma t}\\\\\alpha(t) = -(0.0714)(3.7)e^{-(0.0714) (3)}\\\\\alpha(t) = \boxed{-0.213 rad\sec^2}$

The angular displacement is the INTEGRAL of the angular velocity function.

$\theta (t) = \int\limits^{t_2}_{t_1} {\omega(t)} \, dt\\\\\theta(t) = \int\limits^{2.5}_{0} {\omega_0e^{-\sigma t}dt\\\\$

$\theta(t) = -\frac{\omega_0}{\sigma}e^{-\sigma t}\left \| {{t_2=2.5} \atop {t_1=0}} \right.$

$\theta = -\frac{3.7}{0.0714}e^{-0.0714 t}\left \| {{t_2=2.5} \atop {t_1=0}} \right. \\\\\theta= -\frac{3.7}{0.0714}e^{-0.0714 (2.5)} + \frac{3.7}{0.0714}e^{-0.0714 (0)}$

$\theta = 8.471 rad$

Convert this to rev:

$8.471 rad * \frac{1 rev}{2\pi rad} = \boxed{1.348 rev}$

We can begin by solving for the time necessary for the angular speed to reach 0 rad/sec.

$0 = 3.7e^{-0.0714t}\\\\t = \infty$

Evaluate the improper integral:

$\theta = \int\limits^{\infty}_{0} {\omega_0e^{-\sigma t}dt\\\\$

$\lim_{a \to \infty} \theta = -\frac{\omega_0}{\sigma}e^{-\sigma t}\left \| {{t_2=a} \atop {t_1=0}} \right.$

$\lim_{a \to \infty} \theta = -\frac{3.7}{0.0714}e^{-0.0714a} + \frac{3.7}{0.0714}e^{-0.0714(0)}\\\\ \lim_{a \to \infty} \theta = \frac{3.7}{0.0714}(1) = 51.82 rad$

Convert to rev:

$51.82 rad * \frac{1rev}{2\pi rad} = \boxed{8.25 rev}$

8 0

3 years ago

An unmanned aerial vehicle (UAV) (or uncrewed aerial vehicle, commonly known as a drone) is an aircraft without a human pilot on

DaniilM [7]

Answer:

True

Explanation:

An unmanned areal vehicle is a device that is capable of flying with an on-board power source, receiver, wing propellers and the flight control board.

It functions on the Bernoulli's principle like an airplane does but is controlled remotely by a signal transmitting device with no man on-board.

It is used in various fields like construction, farming, remote sensing, defense, videography and aerial photography.

7 0

3 years ago

The velocity of a car increases from 10 km/h to 50 km/h in 5 seconds. What is its acceleration?

mr Goodwill [35]

Answer:

2.22m/s^2

Explanation:

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3 years ago

What best describes gravity?

Flura [38]

A fundamental force , is your answer .

4 0

3 years ago

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