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3 years ago

9

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

2 answers:

Yuri [45]3 years ago

4 0

<span>The weight of the spacecraft keeps changing.
</span>
<span>The mass of the spacecraft remains the same.

These are the correct answers</span>

san4es73 [151]3 years ago

3 0

Answer:

A)The weight of the spacecraft keeps changing.

D) The mass of the spacecraft remains the same

Explanation:

As we know that the acceleration due to gravity depends on the height from the surface

As we know that the force due to gravity on objects near the surface is given as

$F = \frac{Gm_1m_2}{(R+h)^2}$

here we know that

R = radius of planet

h = height from the surface of planet

So as we move away at more height the gravitational attraction force will keep on decreasing.

This gravitational attraction force of planet is also known as weight so we can say that the weight of the object will keep on changing while object move away.

Also we know that mass of object is quantity of the matter which always remains constant.

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A bowling ball of 35.2 kg, generates 218 kg* m/s units of momentum. What is the velocity of the ball?

Aleonysh [2.5K]

Answer:

6.19 m/s

Explanation:

$p = mv \\ 218 = (35.2)(v ) \\ v = 6.19 \: ms {}^{ - 1}$

7 0

3 years ago

Water is being boiled in an open kettle that has a 0.52-cm-thick circular aluminum bottom with a radius of 12.0 cm. If the water

tangare [24]

Answer:

$T_b=107.3784\ ^{\circ}C$

Explanation:

Given:

thickness of the base of the kettle, $dx=0.52\ cm=5.2\times 10^{-3}\ m$

radius of the base of the kettle, $r=0.12\ m$

temperature of the top surface of the kettle base, $T_t=100^{\circ}C$

rate of heat transfer through the kettle to boil water, $\dot Q=0.409\ kg.min^{-1}$

We have the latent heat vaporization of water, $L=2260\times 10^3\ J.kg^{-1}$

and thermal conductivity of aluminium, $k=240\ W.m^{-1}.K^{-1}$

<u>So, the heat rate:</u>

$\dot Q=\frac{0.409\times 2260000}{60}$

$\dot Q=15405.67\ W$

<u>From the Fourier's law of conduction we have:</u>

$\dot Q=k.A.\frac{dT}{dx}$

$\dot Q=k\times \pi.r^2\times \frac{T_b-T_t}{5.2\times 10^{-3}}$

where:

$A=$ area of the surface through which conduction occurs

$T_b=$ temperature of the bottom surface

$15405.67=240\times \pi\times 0.12^2\times \frac{T_b-100}{5.2\times 10^{-3}}$

$T_b=107.3784\ ^{\circ}C$ is the temperature of the bottom of the base surface of the kettle.

6 0

3 years ago

If you were doing a research study on sleep and student achievement, which

jasenka [17]

Letter D: The amount of sleep a student gets affects student achievement

6 0

3 years ago

Read 2 more answers

Atoms are the smallest portions of an element that retain the original characteristics of the element. True or false

kozerog [31]

Answer:

True

Explanation:

Going even smaller than atoms would get you to subatomic particles such as quarks. From there, it is impossible to distinguish elements. So, yes, atoms are the smallest portions of an element that retains the original characteristic of the element.

4 0

3 years ago

Parallel rays of monochromatic light with wavelength 571nm illuminate two identical slits and produce an interference pattern on

Natasha2012 [34]

Answer:

$8.8\times 10^{-6} W/m^2$

Explanation:

We are given that

Wavelength, $\lambda=571 nm=571\times 10^{-9} m$

$1 nm=10^{-9} m$

R=75 cm= $\frac{75}{100}=0.75 m$

1 m=100 cm

$d=0.640 mm=0.64\times 10^{-3} m$

$1 mm=10^{-3} m$

$a=0.434 mm=0.434\times 10^{-3} m$

$y=0.830 mm=0.830\times 10^{-3} m$

$I_0=5.00\times 10^{-4}W/m^2$

$tan\theta=\frac{y}{R}$

$\theta=\frac{0.830\times 10^{-3}}{0.75\times 10^{-2}}$

$\theta=1.1\times 10^{-3}rad$

$tan\theta\approx \theta$

Because $\theta$ is small.

$\phi=\frac{2\pi dsin\theta}{\lambda}$

$\sin\theta\approx \theta$ ,

Therefore

$\phi=\frac{2\times\pi\times 0.64\times 10^{-3}\times 1.1\times 10^{-3}}{571\times 10^{-9}}$

$\phi=7.74 rad$

$\beta=\frac{2\pi a\theta}{\lambda}$

$\beta=5.3 rad$

$I=I_0cos^2(\frac{\phi}{2})(\frac{sin\frac{\beta}{2}}{\frac{\beta}{2}})^2$

$I=5\times 10^{-4}cos^2(\frac{7.74}{2})(\frac{sin\frac{5.3}{2}}{\frac{5.3}{2}})^2$

$I=8.8\times 10^{-6} W/m^2$

6 0

3 years ago