If heat is gained from a source, it is _________

Signs that say "do not use near an open flame" refer to a(n) A) energy property. B) chemical property. C) physical property. D)

sveta [45]

Answer: B chemical

Explanation: it will make a chemical reaction

8 0

3 years ago

A small mailbag is released from a helicopter that is descending steadily at 3 m/s.

mario62 [17]

Answer:

a) Speed of mailbag after 3 seconds = 32.4 m/s

b) Package is 44.1 meter below helicopter

c) If the helicopter was rising steadily at 3.00 m/s

Speed of mailbag after 3 seconds = 26.4 m/s

Package is 44.1 meter below helicopter

Explanation:

a) We have equation of motion, v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration and t is the time taken.

Initial velocity = 3 m/s, acceleration = 9.8 $m/s^2$ and time = 3 seconds.

v = 3+9.8*3 = 32.4 m/s

Speed of mailbag after 3 seconds = 32.4 m/s

b) We have equation of motion , $s= ut+\frac{1}{2} at^2$ , s is the displacement, u is the initial velocity, a is the acceleration and t is the time.

Velocity of helicopter = 3 m/s, time taken = 3 seconds, acceleration = 0 $m/s^2$ .

$s= 3*3+\frac{1}{2} *0*3^2\\ \\ s=9m$

Distance traveled by helicopter = 9 meter.

Velocity of package = 3 m/s, time taken = 3 seconds, acceleration = 9.8 $m/s^2$ .

$s= 3*3+\frac{1}{2} *9.8*3^2\\ \\ s= 53.1m$

Distance traveled by package = 53.1 meter.

So package is (53.1-9)meter below helicopter = 44.1 m

c) Initial velocity = -3 m/s, acceleration = 9.8 $m/s^2$ and time = 3 seconds.

v = -3+9.8*3 = 26.4 m/s

Speed of mailbag after 3 seconds = 26.4 m/s

Velocity of helicopter = -3 m/s, time taken = 3 seconds, acceleration = 0 $m/s^2$ .

$s= -3*3+\frac{1}{2} *0*3^2\\ \\ s=-9m$

Distance traveled by helicopter = 9 meter.

Velocity of package = -3 m/s, time taken = 3 seconds, acceleration = 9.8 $m/s^2$ .

$s= -3*3+\frac{1}{2} *9.8*3^2\\ \\ s= 35.1m$

Distance traveled by package = 35.1 meter.

So package is (35.1+9)meter below helicopter = 44.1 m

4 0

4 years ago

A plane flies 1,995 miles in a southwesterly direction from Baltimore to Phoenix in 5.00 hours . What is the velocity of the pla

disa [49]

displacement of the plane is given as

$d = 1995 miles$

time taken by the plane

$t = 5.00 hours$

now the velocity is given as

$v = \frac{displacement}{time}$

$v = \frac{1995}{5}$

$v = 399 mi/h$

so the velocity of airplane is 399 mi/h towards South West

4 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.

Explanation:

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

Un leopardo recorre 12.000 yardas, el tigre recorre 1.096.800 centímetros y un puma recorre 10,968 kilómetros. ¿Cuál de los tres

Maksim231197 [3]

El leopardo hizo el mayor recorrido.

7 0

3 years ago

If heat is gained from a source, it is __________ from the source.