Lava is rock that has undergone a physical change and has liquefied. What is known about this change?

(c)

lys-0071 [83]

The answer is c. Twelve wants pass an obsessive frequency of the internet

7 0

4 years ago

Describe the conditions necessary for sublimation to occur.

lozanna [386]

To answer this question with specific values, you would need a phase diagram for the substance in question. In more general terms, the pressure needs to be lower than the pressure of the triple point, the substance must be present in its solid state, and the temperature must rise high enough to produce a gas.

7 0

4 years ago

Read 2 more answers

A 52 kg and a 95 kg skydiver jump from an airplane at an altitude of 4750 m, both falling in the pike position. Assume all value

Scilla [17]

Answer: 52 kg skydiver: 9.09 m/s and 522.55 s

95 kg skydiver: 12.3 m/s and 386.2 s

Explanation: Drag Force is an opposite force when an object is moving in a fluid.

For skydivers, when falling through the air, the forces acting on it are gravitational and drag forces. At a certain point, drag force equals gravitational force, which is constant on any part of the planet, producing a net force that is zero. Since there is no net force, there is no acceleration and, consequently, velocity is constant. When that happens, the person reached the Terminal Velocity.

Drag Force and Velocity are proportional to the squared speed. So, terminal velocity is given by:

$F_{G}=F_{D}$

$mg=\frac{1}{2}C \rho Av_{T}^{2}$

$v_{T}=\sqrt{\frac{2mg}{\rho CA} }$

where

m is mass in kg

g is acceleration due to gravitational force in m/s²

ρ is density of the fluid in kg/m³

C is drag coefficient

A is area of the object in the fluid in m²

Calculating:

The 52kg skydiver has terminal velocity of:

$v_{T}=\sqrt{\frac{2(52)(9.8)}{(1.21)(0.7)(0.14)} }$

$v_{T}=$ 9.09

The 95kg skydiver's terminal velocity is

$v_{T}=\sqrt{\frac{2(95)(9.8)}{(1.21)(0.7)(0.14)} }$

$v_{T}=$ 12.3

The 52 kg and 95kg skydivers' terminal velocity are 9.09m/s and 12.3m/s, respectively.

The time each one will reach the floor will be:

52 kg at 9.09 m/s:

$t=\frac{4750}{9.09}$

t = 522.5

95 kg at 12.3 m/s:

$t=\frac{4750}{12.3}$

t = 386.2

The 52 kg and 95kg skydivers' time to reach the floor are 522.5 s and 386.2 s, respectively.

3 0

3 years ago

1.) What things signal the coming of spring?

olasank [31]

Answer:

In Explanation

Explanation:

The signs of the coming of spring include firstly the sight of Robins. It is believed that the sight and singing of the Robins is considered arrival of spring by many in the US. Secondly, the winter is not yet over but the blooming of Daffodils first of all flowers is indication of the spring. As the air gets warmer the flowers bud and new leaves start growing on trees since the days also begin to get longer providing much warmth which also an indicator of the spring.
Without the axial tilt of our Earth, firstly, the Sun would have remained above the equator (Equinox) forever but fortunately due to the tilt we get equinoxes twice a year and not forever. Moreover, the temperature and precipitation levels would not vary much and the equator would remain always warm and the poles always cold. Secondly, due to the tilt as the Earth orbits around the Sun and with changes in solstices we get variety of the seasons which would have been impossible otherwise.

7 0

3 years ago

A car drives 2 miles north, 4 miles west, 2 miles south and then drives 6 miles east. What is the car's distance?

geniusboy [140]

Answer:

Ok, so the car has traversed a total of 2 + 4 + 2 + 6 = 14 miles.

That's the car's distance! :)

For the displacement, you can draw out a diagram. I'll try my best to make one using a keyboard xDDD

- - - - |

| |

| - - - start - end!

So, this is the journey of the car: Going two up, 4 left, 2 down, and 6 right.

This ends up 2 to the right of the beginning!

That's a 2 mile displacement :)

Can you give me brainliest for my splendid diagram? xD

4 0

3 years ago