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3 years ago

Describe what determines magnetism.

1 answer:

7 0

Magnetism is one aspect of the combined electromagnetic force. It refers to physical phenomena arising from the force caused by magnets, objects that produce fields that attract or repel other objects

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A rocket has initail mass M begins to move from space , with an exhaust constant speed . Find the mass of the rocket while has t

irina1246 [14]

Answer:

$m=\frac{m_{0}}{e}$

Explanation:

Equation of the rocket is,

$m\frac{dv}{dt} =F-v'\frac{dm}{dt}$

Here, v' is the relative velocity of rocket.

In space F is zero.

So,

$m\frac{dv}{dt} =-v'\frac{dm}{dt}\\dv=-v'\frac{dm}{m} \\v=-v'ln\frac{m}{m_{0} }$

Now the momentum can be obtained by multiply by m on both sides.

$P=-v'mln\frac{m}{m_{0} }$

Now for maxima, $\frac{dP}{dm}=0$

$-v'ln\frac{m}{m_{0} }-v'm\frac{m_{0}}{m }m_{0=0$

Now,

$ln(\frac{m}{m_{0} } )=-1\\\frac{m}{m_{0} }=\frac{1}{e} \\m=\frac{m_{0}}{e}$

Therefore, the mass of the rocket while having maximum momentum is $\frac{m_{0}}{e}$

3 0

4 years ago

A rocket rises vertically, from rest, with an acceleration of 3.6m/s^2 until it runs out of fuel at an altitude of 1500m. After

Montano1993 [528]

A. 103.9 m/s

The motion of the rocket until it runs out of fuel is an accelerated motion with constant acceleration a = 3.6 m/s^2, so we can use the following equation

$v^2 -u^2 = 2ad$

where

v is the velocity of the rocket when it runs out of fuel

u = 0 is the initial velocity of the rocket

a = 3.6 m/s^2 is the acceleration

d = 1500 m is the distance covered during this first part

Solving for v, we find

$v=\sqrt{u^2+2ad}=\sqrt{(0^2+2(3.6 m/s^2)(1500 m)}=103.9 m/s$

B. 28.9 s

We can calculate the time taken for the rocket to reach this altitude with the formula

$d=\frac{1}{2}at^2$

where

d = 1500 m

a = 3.6 m/s^2

Solving for t, we find

$t=\sqrt{\frac{2d}{a}}=\sqrt{\frac{2(1500 m)}{3.6 m/s^2}}=28.9 s$

C. 2050.8 m

We can calculate the maximum altitude reached by the rocket by using the law of conservation of energy. In fact, from the point it runs out of fuel (1500 m above the ground), the rocket experiences the acceleration due to gravity only, so all its kinetic energy at that point is then converted into gravitational potential energy at the point of maximum altitude:

$K_i = U_f\\\frac{1}{2}mu^2 = mgh$

where h is distance covered by the rocket after it runs out of fuel, and v=103.9 m/s is the velocity of the rocket when it starts to decelerate due to gravity. Solving for h,

$h=\frac{v^2}{2g}=\frac{(103.9 m/s)^2}{2(9.8 m/s^2)}=550.8 m$

So the maximum altitude reached by the rocket is

$h' = d+h=1500 m +550.8 m=2050.8 m$

D. 39.5 s

The time needed for the second part of the trip (after the rocket has run out of fuel) can be calculated by

$h=\frac{1}{2}gt^2$

where

h = 550.8 m is the distance covered in the second part of the trip

g = 9.8 m/s^2

Solving for t,

$t=\sqrt{\frac{2h}{g}}=\sqrt{\frac{2(550.8 m)}{9.8 m/s^2}}=10.6 s$

So the total time of the trip is

$t'=28.9 s+10.6 s=39.5 s$

E. 200.5 m/s

When the rocket starts moving downward, it is affected by gravity only. So the gravitational potential energy at the point of maximum altitude is all converted into kinetic energy at the instant the rocket hits the ground:

$\frac{1}{2}mv^2 = mgh$

where

v is the final velocity of the rocket

h = 2050.8 m is the initial altitude of the rocket

Solving for v,

$v=\sqrt{2gh}=\sqrt{2(9.8 m/s^2)(2050.8 m)}=200.5 m/s$

F. 60 s

We need to calculate the time the rocket takes to fall down to the ground from the point of maximum altitude, and that is given by

$h'=\frac{1}{2}gt^2$

where

h' = 2050.8 m

g = 9.8 m/s^2

Solving for t,

$t=\sqrt{\frac{2h'}{g}}=\sqrt{\frac{2(2050.8 m)}{9.8 m/s^2}}=20.5 s$

So the total time of the trip is

$t''=39.5 s+20.5 s=60 s$

6 0

4 years ago

What is the atomic weight of Fe2 O3

Oksi-84 [34.3K]

159.69g/mol Because you can covert and you also learn in science class

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4 years ago

What would happen to a vacant lot in your community if it were left alone for the next 25 years.

topjm [15]

In my county Contra Costa County, California a property (with a value of greater than 15.00) left abandoned after 3 years the County needs to publish in a newspaper the location of the property and try and locate the lawful owners. Often their may be unpaid property taxes and penalties that need to be paid if the owner is found and wishes to reclaim the property. Sometimes due to deaths of previous owners without a trust or will it is difficult to find if their are any heirs to the property. If no one responds within 45 days of the publication the property will belong to the county and no longer claimed. If you feel you have any property or cash that belongs to you every State has a government site called unclaimed property. You can put in your name or a relatives name and if it belongs to you there is a form to be filled out and if you are the rightful owner you will receive it.

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4 years ago

Can somebody please help me again! picture attached

-Dominant- [34]

What school u go to

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3 years ago