Which of the Materials are conductors?(select all apply)

4. Joe and his brother Bo have a combined mass of 200.0 kg and are zooming along in

puteri [66]

Answer:

Joe & Bo's car: 200.0 kg + 100.0 kg = 300.0 kg; Melinda's car: 25.0 kg + 100.0 kg = 125.0 kg

so the answer is 125.0kg

6 0

3 years ago

Diagnostic ultrasound of frequency 4.50 MHz is used to examine tumors in soft tissue. (a) What is the wavelength in air of such

mafiozo [28]

(a) $7.62 \times 10^{-5} m$ is the wavelength in air of such a sound wave.

(b) $3.33 \times 10^{-4}\ m$ is the wavelength of this wave in tissue.

<u>Explanation:</u>

Frequency and wavelength can be related by the equation,

Velocity = Wavelength x Frequency

$v=\lambda \times f$

where,

v - velocity of light for all EM (electromagnetic) waves in vacuum

Given:

f - 4.50 MHz = $4.50 \times 10^{6} \mathrm{Hz}$

a) To find the wavelength in air

We know,

Speed of sound in air = 343 m/s

Apply given frequency and speed of sound in air, we get

$\lambda=\frac{v}{f}=\frac{343}{4.5 \times 10^{6}}=76.2 \times 10^{-6}=7.62 \times 10^{-5}\ \mathrm{m}$

b) If the speed of sound in tissue is 1500 m/s, find the wavelength of this wave in tissue

Speed of sound in tissue, v = 1500 m/s

$\lambda=\frac{v}{f}=\frac{1500}{4.5 \times 10^{6}}=333.33 \times 10^{-6}=3.33 \times 10^{-4} \mathrm{m}$

4 0

3 years ago

Water enters a house at 1.5 m/s through a pipe with an inside radius of 1.0cm and at a pressure of 400,000 Pa. The water then tr

kupik [55]

Answer:

pressure of the water = 3.3 × $10^{5}$ pa

Explanation:

given data

velocity v1 = 1.5 m/s

pressure P = 400,000 Pa

inside radius r1 = 1.00 cm

pipe radius r2 = 0.5 cm

h1 = 0 (datum at inlet)

h2 = 5.0 m (datum at inlet)

density of water ρ = 1000 kg/m³

to find out

pressure of the water

solution

we consider here flow speed in bathroom that is = v2 and Pressure in bathroom is = P2

here we will use both continuity and Bernoulli equations

because here we have more than one unknown so that

v1 × A1 = v2 × A2 × P1 + ρ g h1 + (0.5)ρ v1² = P2 + ρ g h2 + (0.5) ρ v2²

now we use here first continuity equation for get v2

v2 = $v1 \frac{A1}{A2}$

v2 = $1.5 \frac{\pi * 0.01^2}{\pi * 0.005^2}$

v2 = 6 m/s

and now we use here bernoulli eqution for find here p2 that is

P2 = P1 - 0.5× ρ ×(v2² - v1²) - ρ g (h2- h1 )

P2 = 400000 - 0.5× 1000 ×(6² - 1.5²) - 1000 × 9.81 × (5-0 )

P2 = 3.3 × $10^{5}$ pa

3 0

3 years ago

A closed box is filled with dry ice at a temperature of -87.1°C, while the outside temperature is 17.6°C. The box is cubical, me

natta225 [31]

Answer:

K=24.17 x 10⁻² J s⁻¹c⁻¹m⁻¹

Explanation:

Rate of flow of heat through a material is given by the following expression

$\frac{Q}{t} =\frac{KA\delta T}{d}$

where Q is amount of heat flowing in time t through area A and a medium of thickness d having two faces at temperature difference δT . K is thermal conductivity of the medium .

Here Q = 3.34 x 10⁶/6 , t = 24 x 60 x 60 = 86400 s , A = .332 X .332 = .0110224 m² , δT = 104.7

Put these values here

$\frac{3.34\times10^6}{6\times86400}= \frac{k\times.011224\times104.7}{4.41\times10^{-2}}$

$K=\frac{3.34\times4.41\times10^4}{6\times86400\times.011224\times104.7}$

K=24.17 x 10⁻² J s⁻¹c⁻¹m⁻¹

4 0

3 years ago

What best describes myotibrils

krok68 [10]

Myofibrils are composed of long proteins such as actin, myosin, and titin, and other proteins that hold them together. These proteins are organized into thin filaments and thick filaments, which repeat along the length of the myofibril in sections called sarcomeres. Muscles contract by sliding the thin (actin) and thick (myosin) filaments along each other.

8 0

3 years ago