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3 years ago

Which of the following best describes a galaxy?

Physics

1 answer:

valentinak56 [21]3 years ago

4 0

Answer:

B-Large groups of stars held together by gravity

Explanation:

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Assume you have a rocket in Earth orbit and want to go to Mars. The required change in velocity is ΔV≈9.6km/s . There are two op

Nostrana [21]

Answer: Part 1: Propellant Fraction (MR) = 8.76

Part 2: Propellant Fraction (MR) = 1.63

Explanation: The Ideal Rocket Equation is given by:

Δv = $v_{ex}.ln(\frac{m_{f}}{m_{e}} )$

Where:

$v_{ex}$ is relationship between exhaust velocity and specific impulse

$\frac{m_{f}}{m_{e}}$ is the porpellant fraction, also written as MR.

The relationship $v_{ex}$ is: $v_{ex} = g_{0}.Isp$

To determine the fraction:

Δv = $v_{ex}.ln(\frac{m_{f}}{m_{e}} )$

$ln(MR) = \frac{v}{v_{ex}}$

Knowing that change in velocity is Δv = 9.6km/s and $g_{0}$ = 9.81m/s²

Note: Velocity and gravity have different measures, so to cancel them out, transform km in m by multiplying velocity by 10³.

Part 1: Isp = 450s

$ln(MR) = \frac{v}{v_{ex}}$

ln(MR) = $\frac{9.6.10^{3}}{9.81.450}$

ln (MR) = 2.17

MR = $e^{2.17}$

MR = 8.76

Part 2: Isp = 2000s

$ln(MR) = \frac{v}{v_{ex}}$

ln (MR) = $\frac{9.6.10^{3}}{9.81.2.10^{3}}$

ln (MR) = 0.49

MR = $e^{0.49}$

MR = 1.63

8 0

3 years ago

2. What would be the acceleration of the clown at 5 s? (A) 1.6 m/s2 (B) 8.0 m/s2 (C) 2.0 m/s2 (D) 3.4 m/s2 3. After 12 seconds,

Neko [114]

Is there an image that goes with this question?

7 0

2 years ago

A mosquito of mass 0.15 mg is found to be flying at a speed of 50 cm/s with an uncertainty of 0.5 mm/s. (a) How precisely may it

amid [387]

Answer:

a) Δx = t 0.05 + 0.5

, Δx = 0.5 cm, b) Do not present any problem

Explanation:

The kinematic equation for constant speed is

v = x / t

x = v t

a) the uncertainty can be calculated with

Δx = dx /dv Δv + dx /dt Δt

Δx = t Δv + v Δt

Speed is

v = (50.00 ± 0.05) cm / s

The most common uncertainty for the time of Δt = 0.01 s

We replace

Δx = t 0.05 + 50 0.01

Δx = t 0.05 + 0.5

We must know the time to have an explicit value, if we assume that the measure was t = 1s

Δx = 0.5 cm

Do not present any problem since its value is not very small, we must take as soon as the quantum effects and the velocity are not so high that we must take into account the relativistic effects

5 0

3 years ago

What is the percent increase in the vapor pressure of water when the temperature increases by 1 °c from 14°c to 15°c.

Artemon [7]

The Vapor Pressure of water increases by 5.1%. when the temperature increases by 1 °c from 14°c to 15°c.

The vapor pressure of a liquid, sometimes referred to as the equilibrium pressure of a vapor above its liquid, is the pressure of the vapor produced by the evaporation of a fluid (or solid) over a sample of the liquid (or solid) in such a closed container (or solid).

Vapor pressure is the term for the force that is produced as liquids evaporate. Three factors commonly have an effect on a vapor press: surface area, intermolecular forces, and temperature. The vapor pressures of molecules change with temperature.

To know more about Vapor Pressure visit : brainly.com/question/14718830

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6 0

1 year ago

A gymnast with mass m1 = 44 kg is on a balance beam that sits on (but is not attached to) two supports. The beam has a mass m2 =

SVEN [57.7K]

Answer:

Explanation:

e. At the right edge of the beam

Check attachment for other solution

4 0

3 years ago