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3 years ago

14

Which of the following describes a physical change? A. A marshmallow burns over an open flame. B. Icicles melt from a rooftop. C

. A cat eats a piece of fish. D. Milk turns sour.

1 answer:

AnnZ [28]3 years ago

5 0

Answer:

B

Explanation:

Icicles melt from a rooftop

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A ray of light contains two colors: red with wavelength of 660 nm and blue with wavelength 470 nm. The ray passes through two na

densk [106]

Answer:

The distance on the screen between the first-order bright fringes for each wavelength is 3.17 mm.

Explanation:

Given that,

Wavelength of red = 660 nm

Wavelength of blue = 470 nm

Separated d= 0.30 mm

Distance between screen and slits D= 5.0 m

We need to calculate the distance for red wavelength

Using formula for distance

$y=\dfrac{\lambda D}{d}$

Where, D = distance between screen and slits

d = separation of slits

Put the value into the formula

$y=\dfrac{660\times10^{-9}\times5.0}{0.30\times10^{-3}}$

$y=11\ mm$

For blue wavelength,

Put the value into the formula again

$y'=\dfrac{470\times10^{-9}\times5.0}{0.30\times10^{-3}}$

$y'=7.83\ mm$

We need to calculate the distance on the screen between the first-order bright fringes for each wavelength

Using formula for distance

$\Delta y=y-y'$

$\Delta y=11-7.83$

$\Delta y=3.17\ mm$

Hence, The distance on the screen between the first-order bright fringes for each wavelength is 3.17 mm.

4 0

4 years ago

What is the molar mass of an ideal gas if a 0.800 g sample of this gas occupies a volume of 200. mL at 50.0 oC and 720. mm Hg?

Paladinen [302]

PV=nRT
(720/760)(0.200)=(0.800/x)(0.08206)(323.15)
(0.1894736842)=(0.800/x)(0.08206)(323.15)
.0071451809=(0.800/x)
x=MM=111.9635758 g/mol

7 0

3 years ago

A 10 kg turkey, He kicks the 0.5 kg ball with a force of 50N for 0.2 seconds and the ball flies straight away horizontally from

Harman [31]

Answer:

a. 20m/s

b.50N

c. Turkey has a larger mass than the ball. Neglible final acceleration and therefore remains stationery.

Explanation:

a. Given the force as 50N, times as 0.2seconds and the weight of the ball as 0.5 kg, it's final velocity can be calculated as:

$F\bigtriangleup t=m\bigtriangleup v\\\\50N\times 0.2s=0.5kg\times \bigtriangleup v\\\\\bigtriangleup v=2(50N\times0.2)\\\\=20m/s$

Hence, the velocity of the ball after the kick is 20m/s

b.The force felt by the turkey:

#Applying Newton's 3rd Law of motion, opposite and equal reaction:

-The turkey felt a force of 50N but in the opposite direction to the same force felt by the ball.

c. Using the law of momentum conservation:

-Due to ther external forces exerted on the turkey, it remains stationery.

-The turkey has a larger mass than the ball. It will therefore have a negligible acceleration if any and thus remains stationery.

-Momentum is not conserved due to these external forces.

5 0

4 years ago

‼️‼️ Please help, urgent ‼️‼️ (check photo)

Alex787 [66]

Answer: The force constant k is 10600 kg/s^2

Step by step:

Use the law of energy conservation. When the elevator hits the spring, it has a certain kinetic and a potential energy. When the elevator reaches the point of still stand the kinetic and potential energies have been transformed to work performed by the elevator in the form of friction (brake clamp) and loading the spring.

Let us define the vertical height axis as having two points: h=2m at the point of elevator hitting the spring, and h=0m at the point of stopping.

The total energy at the point h=2m is:

$E_{tot}=E_{kin}+E_{pot}\\E_{tot}= \frac{1}{2}mv^2+mg\Delta h = \frac{1}{2}2000 kg 4^2\frac{m^2}{s^2}+2000kg\, 9.8\frac{m}{s^2}2m=55200\,kg\frac{m^2}{s^2}$

The total energy at the point h=0m is:

$E_{tot}=E_{kin}+E_{pot}+Work=0+0+ Work\\E_{tot} =F_{friction}\Delta h+\frac{1}{2}k (\Delta h)^2=17000N\cdot 2m+\frac{1}{2}k\cdot 2^2 m^2$

The two Energy values are to be equal (by law of energy conservation), which allows us to determine the only unknown, namely the force constant k:

$17000N\cdot 2m+\frac{1}{2}k\cdot 2^2 m^2 = 55200 \,kg\frac{m^2}{s^2}\\k = \frac{55200-34000}{2}\,\frac{kg}{s^2}=10600\frac{kg}{s^2}$

5 0

3 years ago

Provided following are four different ranges of stellar masses. Rank the stellar mass ranges based on how many stars in each ran

Julli [10]

Highest to lowest number:

-less than 1 solar mass

-between 1 and 10 solar masses

-between 10 and 30 solar masses

-between 30 and 60 solar masses

<h3>What is Stellar masses ?</h3>

Stellar mass is a phrase that is used by astronomers to describe the mass of a star. It is usually enumerated in terms of the Sun's mass as a proportion of a solar mass (M☉).

Hence, the bright star Sirius has around 2.02 M☉.

A star's mass will vary over its lifetime as mass is lost with the stellar wind or ejected via pulsational behavior, or if additional mass is accreted, such as from a companion star.

Learn more about Stellar masses here:

brainly.com/question/12790561

#SPJ4

3 0

2 years ago