What is a rock that is full of tiny connected air spaces

Medical cyclotrons need efficient sources of protons to inject into their center. In one kind of ion source, hydrogen atoms (i.e

antoniya [11.8K]

Answer:

$r=5.278\times 10^{-4}\ m$

Explanation:

Given that:

magnetic field intensity, $B=0.07\ T$

kinetic energy of electron, $KE=1.2\ eV= 1.2\times 1.6\times 10^{-19}\ J= 1.92\times 10^{-19}\ J$

we have mass of electron, $m=9.1\times 10^{-31}\ kg$

Now, form the mathematical expression of Kinetic Energy:

$KE= \frac{1}{2} m.v^2$

$1.92\times 10^{-19}=0.5\times 9.1\times 10^{-31}\times v^2$

$v^2=4.2198\times 10^{11}$

$v=6.496\times 10^6\ m.s^{-1}$

from the relation of magnetic and centripetal forces we have the radius as:

$r=\frac{m.v}{q.B}$

$r=\frac{9.1\times 10^{-31}\times 6.496\times 10^6 }{1.6\times 10^{-19}\times 0.07}$

$r=5.278\times 10^{-4}\ m$

6 0

3 years ago

How do very high density objects appear in an ultrasound?

evablogger [386]

Density is entirely unrelated to an object's size. It is a property of a given

7 0

3 years ago

A rock is lifted by a machine to a height of 10m. If it has a mass of 22 kilograms

zmey [24]

Answer:

2156J

Explanation:

Given parameters:

Height of lift = 10m

Mass = 22kg

Unknown:

Work done by the machine = ?

Solution:

Work done is the force applied to move a body through a certain distance.

So;

Work done = Force x distance

Here;

Work done = mass x acceleration due to gravity x height

Work done = 22 x 9.8 x 10 = 2156J

5 0

3 years ago

In a controlled experiment, a scientist is studying how long it takes feathers of different sizes to fall to the ground. What is

nikdorinn [45]

Answer: independent variable: Size of the feather.

Explanation:

In an experiment, the manipulated/independent variable is, as the name implies, the variable that the scientist can control.

In this case, the scientist has only one variable that he can control at will, and this is the size of the feather (he can choose which feather he uses for the experiment)

So the manipulated variable will be the size of the feather.

And the dependent variable is the one that "answers" to the changes in the manipulated variable.

In this case, will be the time that it takes to the feather to fall to the ground.

5 0

3 years ago

A room has a wall with an R value of 18 F sq.ft. hr/BTU. The room is 15 feet long and 11 feet wide with walls that are 9 ft high

seropon [69]

Answer:

The heat transferred through the wall that day is 13728 BTUs

Explanation:

Here, we have the area of the wall given as

Area of wall = 2 × Length × Height + 2 × Width × Height

Length = 15 feet

Width = 11 Feet and

Height = 9 feet

Therefore, the area = 2×15×9 + 2×11×9 = 468 ft²

Temperature difference is given by

Average outside temperature - Wall temperature = 40 - 18 = 22 °F

Therefore the heat transferred through the wall that day (24 hours) at 18 sq.ft. hr/BTU is given by;

468 × 22 × 24/18 = 13728 = 13728 BTUs.

5 0

3 years ago