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Sunny_sXe [5.5K]

4 years ago

9

Patients with brain tumors may elect to have a procedure known as Gamma Knife. In a typical Gamma Knife procedure gamma rays are

directed toward a tumor with contact to surrounding tissues.
Limiting contact between gamma rays and healthy tissue is important because

2 answers:

Allushta [10]4 years ago

6 0

Thinking not sure but gammer rays are high energy and may cause damage to healthy cells

marysya [2.9K]4 years ago

5 0

Answer: B) gamma rays are high energy and may cause damage to healthy cells.

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Which quantities are vectors

Zarrin [17]

Answer:

For example, displacement, velocity, and acceleration are vector quantities, while speed (the magnitude of velocity), time, and mass are scalars. To qualify as a vector, a quantity having magnitude and direction must also obey certain rules of combination.

Explanation:

8 0

3 years ago

Read 2 more answers

A permeability test was run on a compacted sample of dirty sandy gravel. The sample was 175 mm long and the diameter of the mold

LUCKY_DIMON [66]

Answer:

(a). The coefficient of permeability is $8.6\times10^{-3}\ cm/s$ .

(b). The seepage velocity is 0.0330 cm/s.

(c). The discharge velocity during the test is 0.0187 cm/s.

Explanation:

Given that,

Length = 175 mm

Diameter = 175 mm

Time = 90 sec

Volume= 405 cm³

We need to calculate the discharge

Using formula of discharge

$Q=\dfrac{V}{t}$

Put the value into the formula

$Q=\dfrac{405}{90}$

$Q=4.5\ cm^3/s$

(a). We need to calculate the coefficient of permeability

Using formula of coefficient of permeability

$Q=kiA$

$k=\dfrac{Q}{iA}$

$k=\dfrac{Ql}{Ah}$

Where, Q=discharge

l = length

A = cross section area

h=constant head causing flow

Put the value into the formula

$k=\dfrac{4.5\times175\times10^{-1}}{\dfrac{\pi(175\times10^{-1})^2}{4}\times38}$

$k=8.6\times10^{-3}\ cm/s$

The coefficient of permeability is $8.6\times10^{-3}\ cm/s$ .

(c). We need to calculate the discharge velocity during the test

Using formula of discharge velocity

$v=ki$

$v=\dfrac{kh}{l}$

Put the value into the formula

$v=\dfrac{8.6\times10^{-3}\times38}{17.5}$

$v=0.0187\ cm/s$

The discharge velocity during the test is 0.0187 cm/s.

(b). We need to calculate the volume of solid in the ample

Using formula of volume

$V_{s}=\dfrac{M_{s}}{V_{s}}$

Put the value into the formula

$V_{s}=\dfrac{4950\times10^{-3}}{2710}$

$V_{s}=1826.56\ cm^3$

We need to calculate the volume of the soil specimen

Using formula of volume

$V=A\times L$

Put the value into the formula

$V=\dfrac{\pi(17.5)^2}{4}\times17.5$

$V=4209.24\ cm^3$

We need to calculate the volume of the voids

$V_{v}=V-V_{s}$

Put the value into the formula

$V_{v}=4209.24-1826.56$

$V_{v}=2382.68\ cm^3$

We need to calculate the seepage velocity

Using formula of velocity

$Av=A_{v}v_{s}$

$v_{s}=\dfrac{Av}{A_{v}}$

$v_{s}=\dfrac{V}{V_{v}}\times v$

Put the value into the formula

$v_{s}=\dfrac{4209.24}{2382.68}\times0.0187$

$v_{s}=0.0330\ cm/s$

The seepage velocity is 0.0330 cm/s.

Hence, (a). The coefficient of permeability is $8.6\times10^{-3}\ cm/s$ .

(b). The seepage velocity is 0.0330 cm/s.

(c). The discharge velocity during the test is 0.0187 cm/s.

8 0

4 years ago

What is kinematics?<br>explain!!~

MAXImum [283]

<h3>What is Kinematics?</h3>

Kinematics can be explained as science that is used in describing the motion of objects, and these description can be made by the use of;

words
diagrams
numbers
graphs

Kinematics which is a mechanics helps to develop sophisticated mental models which helps in serve describing motion of real-world objects.

Learn more about Kinematics at:

brainly.com/question/24717901

8 0

2 years ago

The highest frequencies humans can hear is about 20000 Hz. What is the wavelength of sound in air at this frequency? The speed o

White raven [17]

Answer:

0.017 m

Explanation:

Wavelength: This can be defined as the distance covered in one complete oscillation by a wave. The S.I unit of wave length is meter (m).

The expression for wave length is given as

v = λf ............................... Equation 1

Where v = speed of sound in air, λ = wave length of sound, f = frequency of sound.

make λ the subject of the equation,

λ = v/f ............................... Equation 2

Given: v = 340 m/s, f = 20000 Hz

Substitute into equation 2

λ = 340/20000

λ = 0.017 m.

Hence the wave length of sound in air = 0.017 m

4 0

3 years ago

A horizontal spring with a spring constant 100 N/m is compressed 20cm and used to launch a 2.5kg box across a frictionless, hori

Verdich [7]

Answer:

d = 0.544 m

Explanation:

To solve this problem we must work in two parts: one when the surface has no friction and the other when the surface has friction

Let's start with the part without rubbing, let's find the speed that the box reaches., For this we use the conservation of mechanical energy in two points: maximum compression and when the box is free (spring without compression)

Initial, maximum compression

Em₀ = Ke = ½ k x²

Final, free box without compressing the spring

$Em_{f}$ = K = ½ m v²

Emo = $Em_{f}$

½ k x² = ½ m v²

v = √ (k / m) x

Let's reduce the SI units measures

x = 20 cm (1m / 100cm) = 0.20 m

v = √ (100 / 2.5) 0.20

v = 1,265 m / s

Let's work the second part, where there is friction. In this part the work of the friction force is equal to the change of mechanical energy

$W_{fr}$ = ΔEm = $Em_{f}$ - Em₀

$W_{fr}$ = - fr d

Final point. Stopped box

$Em_{f}$ = 0

Starting point, starting the rough surface

Em₀ = K = ½ m v²

With Newton's second law we find the force of friction

fr = μ N

N-W = 0

N = W = mg

fr = μ mg

-μ m g d = 0 - ½ m v²

d = ½ v² / (μ g)

Let's calculate

d = ½ 1,265² / (0.15 9.8)

d = 0.544 m

6 0

3 years ago