Rock Definition and 347 Threads

I was thinking about this question: So if a rock fell 20,000 meters to Earth assuming no air resistance and no other gravitational forces from anything but Earth, how long would it take the rock to hit Earth? Keep in mind acceleration is changing through the gravity equation as the rock gets...

Particle Data Group - 2017 Review has some strong lower limits for the mass scales of possible quark and lepton compositeness, or at least the compositeness of the easier-to-study ones, like up and down quarks and also electrons. The limits are well into the TeV range, though they are somewhat...

Homework Statement A rock approaches the foot of a hill with a speed of 16 m/s. The hill has a slope of 23 degrees, how far up the hill does the rock travel? Homework Equations KE = PE The Attempt at a Solution I tried mv2/2 = mgy but I know this isn't right since I don't use theta at all...

Homework Statement These are two conceptual questions we were given recently. It's strange how mathematically I regularly do much harder problems but these caught me out a bit Q1. If a one snooker ball hits another ball moving at constant speed, why does the second ball move? Surely due to...

https://drive.google.com/file/d/0B6vFDqtp6QNEOW9CeUFYOWRGczA/view?usp=sharing The pictures in this post are of a "hammerstone," or pounder. It was found next to a large lower grinder (metate, quern, whatever term you prefer). It is 11 cm high and 13 cm wide. It most likely cracked from heat...

Let's consider a game of paper, scissor, rock. We have two players: player A and player B. Player A always do paper; player B always uses a strategy, where he tosses a die, and if it comes out 1 or 2- he goes rock, if it comes out 3 or 4- he goes paper, and if it comes out 5 or 6- he goes...

Could we classify oil shale as a biochemical sedimentary rock ? Oil shale is a muddy rock contains Kerogen. So I think in oil shale to be a mixture of Kerogen and mud sediments, and that's not the case, for instance, with the biochemical limestone where the solid remains of the living organisms...

I just recently read about how we got to know the true age of the Earth but I am a bit confused and curious about one thing. The mineral or rock is initially going to be a uranium right? If it is, isn't all of it going to decay at the same rate? I know that a radioactive reaction is spontaneous...

Can't help seeing some similarities. If Newton were alive today I wonder if he would be a fan of Led Zeppelin. Perhaps he would occasionally fill in for Robert Plant.

Can anyone help please, I have been searching for vintage valve amplifier circuit diagrams and components. I need help in finding valves, transformers, and diagrams. I intend to build amplifiers for a rock band so i would like to build one with a 3KW output if that is feasible. Thanks for any...

Homework Statement A hot rock ejected from a volcano's lava fountain cools from 1100º C to 40.0º C and its entropy decreases by 950 J/K. How much heat transfer occurs from the rock? (Source: OpenStax "College Physics for AP Students", Chapter 15.6) Homework Equations I used the equation ΔSh +...

I came across this rock and it just seemed out of place and was wondering if anyone could help identify it. I am in the Western Upper michigan area.

Hi Guys, I solved two questions below. Just need some feedback to make sure I solved them correctly. Thanks a bunch. 1. Homework Statement A car of mass 1.4 tonnes (1400 kg) traveling down the highway at 120 km/h has a F air of 1800 N acting against it. What force must be applied by the...

Homework Statement A rock is thrown horizontally off a 56 m high cliff overlooking the ocean. And the sound of the splash is heard 3.60 seconds later. Speed of sound in air is 343 m/s. What was the initial velocity of the rock? 2. Homework Equations The Attempt at a Solution Okay so I know...

Homework Statement Rock is falling from 10meters 18km/h speed , what is speed of rock just before it touches the ground Homework EquationsThe Attempt at a Solution So in meters its like 5m/s and h=10m so t=2s if h=d , v=t*d=2s*10m=20m/s but i think i somehow should include gravity too so I am...

Homework Statement [/B] You throw a small rock straight up from the edge of a highway bridge that crosses a river. The rock passes you on its way down, 5.00 s after it was thrown. What is the speed of the rock just before it reaches the water 21.0 m below the point where the rock left your...

Can anyone help me identify this rock a friend of mine said it might be a nest of some sort or an egg curious to know if anybody has any ideas on what it is thank you

Homework Statement A small spherical rock of mass collides in space with a large spherical rock of mass as indicated in the diagram. After the collision the rocks stick together to form a single spherical object. https://postimg.org/image/fltmg3bj5/ (New here so I've no clue how to upload...

$\tiny{205_o6_05_velocity}$ The equation for a free fall at the surface of celestial body in outer space ($s$ in Meters, $t$ in seconds.)\\ is $\displaystyle s=2.38t^2$ How long does it take a rock falling from rest to reach a velocity of $\displaystyle 25.7 \frac{m}{sec}$ on this celestial...

I have a rock that I found while on a college class outing in Eastern Oregon. It is hollow inside and has multiple objects inside that rattle. I was told by a professor that isn't was formed when lava was ejected into the air and as it fell, it sort of ballooned out and solidified with smaller...

Homework Statement A rock is thrown off of a 32 m high building with a horizontal velocity of 5 m/s. What is the vertical velocity when it reaches 6 m from the ground? Use g = 10 m/s^2 A) 11 m/s B) 120 m/s C) 23 m/s D) 520 m/s E) 16 m/s Homework Equations Kinematics I think The Attempt at a...

Homework Statement A footballer kicks the rock off the cliff, with a horizontal velocity. The cliff's height is 40.0m. The rock falls in a lake. The footballer hears the "splash" 3.00s later. Sound travels through air with a velocity of 343 m/s. What is the rock's initial velocity? a = -g =...

Homework Statement A 3 wt% HF / 12 wt% HCL treatment is injected without an HCL preflush into a sandstone reservoir containing 10% CaCO3. If half of the HF is consumed in reaction with CaCO3 to form CaF2, what will be the next porosity change, considering both CaCO3 dissolution and CaF2...

Homework Statement Stretchable ropes are used to safely arrest the fall of rock climbers. Suppose one end of a rope with unstretched length ##l## is anchored to a cliff and a climber of mass m is attached to the other end. Ehrm the climber is a height ##l## above the anchor point, he slips and...

< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown >[/color] The question states a stone is thrown off a cliff horizontal and it eventually hits the ground. A second stone is dropped from rest at the same height and it hits the ground too. The...

Homework Statement Can someone please help me with this A level physics question on Mechanics. Help will be appreciated. The picture of question is attached. :D Thank you Homework EquationsThe Attempt at a Solution [/B]sin20x590=201.79N or cos70x590=201.79N

Homework Statement Identify which rock pictured was most likely the result of a volcanic eruption. No info is provided besides the following pictures which I managed to find on the internet: https://commons.wikimedia.org/wiki/File:Volcanic_rock_from_Unzen.jpg...

Homework Statement A rock is thrown straight upward from the edge of a 30m cliff, rising 10m, then falling all the way down the base of the cliff.Homework EquationsThe Attempt at a Solution Well, because the rock was thrown 10m up, and then it came all the way down, I added those quantities...

Homework Statement One side of the roof of a house slopes up at 37.0°. A roofer kicks a round, flat rock that has been thrown onto the roof by a neighborhood child. The rock slides straight up the incline with an initial speed of 15.0 m/s. The coefficient of kinetic friction between the rock...

Hello! (Wave) A ship that is at the position $(1,0)$ of a chart ( with the north at the positive direction $y$) "sees" a rock at the position $(2,4)$. Which is the vector that connects the ship with the rock? What angle $\theta$ does this vector form with the direction of the north? I have...

So I am trying to make rock candy. I made my saturated solution of sugar about two and a half days ago and so far there is almost no crystallization on the skewer that I have sitting in the middle of the solution. But there is a layer of sugar crystals covering the top. Should I break that top...

I am a Ph.D student currently interested in fluid flow in porous media (rocks in my case). I am currently trying to find the range of values for the contact angle in air-water-sandstone systems at shallow reservoir conditions (say 7.5MPa and 35 degrees C). The only value I have managed to come...

Suppose a rock sample at the time of its formation 3.6 × 10^9 years ago contained N0[87Rb] rubidium atoms 87 (87Rb), N0[87Sr] strontium atoms 87 (87Sr) and N0[86Sr] strontium atoms 86 (86Sr). From the relative abundance of the three species at the height of the rock formation yielded the...

A rock with a weight of 10 N is resting on a table. A student makes a number of statements about this situation, are they right or wrong? 1. "The weight of the rock is a force of 10 N by gravity in the downward direction" I don't see anything wrong with this. 2. "The reaction force to this...

Homework Statement A series of shear tests were performed on a weak rock. Each test was carried out until the sample sheared, and the principal stresses for each test were: S. No.--- σ3 (KN/m2) --- σ1 (KN/m2) 1 --- 200 --- 570 2 --- 300...

Homework Statement A 65kg rock climber is abseiling down a rock, consider the situation when he's in equilibrium and standing at an angle on the surface of the rock, hanging from a rope. The rope is at an angle of 40 degrees to the horizontal, calculate the tension in the rope Homework...

The mid-end and high-end rock n roll performance bands have technical people or technologists to help with equipment (electric guitars, amplifiers, and variety of devices used with them; modifications, and repairs). Exactly what do these technical know, and how do they learn it? There have...

Homework Statement At which minimum velocity should you throw the ball horizontally if you are standing on a hemispherical rock of radius R so that it at no point touches the rock and lands at the minimum distance from the rock horizontally. Find the expression that solves for initial velocity...

Homework Statement 6 Earthquakes produce transverse and longitudinal seismic waves that travel through rock. Figure 8 shows the displacement of the particles of rock at a given instant, for different positions along a transverse wave. Figure 8: (b) Describe the motion of the rock particle...

A couple of simple, (maybe dumb) questions - Consider a string, maybe a meter long, with one end attached to a small rock, and the other end attached to the shaft of a motor standing so the shaft points upwards. When the motor is turned off, the string hangs limp. When the motor runs, the rock...

Homework Statement A 250 gram rock is thrown with a speed of 30.0 m/s. It has a speed of 22.5 m/s just before it strikes the ground. Determine the work done by air resistance. There is also a diagram which yields more information. The rocks path is horizontal and it strikes the corner of a...

From Google news, http://www.theregister.co.uk/2015/02/18/meteor_explodes_over_Earth's_beaver_in_hot_nasa_video/ Simple question, if you play the video in the link above the light from the meteor flairs up into a very large ball of light. Why don't we continue to see a relatively small point...

Homework Statement Huge volumes of igneous rock can be erupted and/or intrude in the middle of tectonic plates? True or False Homework EquationsThe Attempt at a Solution I am being thrown off by this rather simple problem. I understand that at the border of tectonic plates, a lot is...

I ran into a link from a NASA page over to an Astrobiology webzine. In the article it referenced "sedimentary rock" on Mars. I don't really care about all the other claims of this article, some rather fantastic claims frankly. Rather I am interested in the use of the phrase sedimentary...

On youtube, I came across to one of many videos trying to explain General Relativity. One of the comments was interesting to me: "I understand how gravity causes an object with velocity to go in curves or to orbit, due to the curvature of space-time: the object thinks that it's traveling in a...

Here is the question: A spring is compressed 20cm. When it is released, it exerts an average force of 57.2 N on a 7.3 kg rock, shooting it across a frictionless floor. Determine the speed of the rock as it leaves the spring. Homework Equations W=change in energy Work energy theorem W=Fd The...

Homework Statement I'm taking grade 12 U physics and I'm having a really difficult time understanding the answers given compared to the answers I arrive at. For example: The question reads: A rock was thrown horizontally from a 25.0 m high cliff and landed 15.0 m from the base of the cliff...

Homework Statement You hold a bucket in one hand. In the bucket is a 480g rock. You swing the bucket so the rock moves in a vertical circle 2.8m in diameter. What is the minimum speed the rock must have at the top of the circle if it is to always stay in contact with the bottom of the bucket...

Homework Statement The problem is here: Homework Equations q = heat flow k = thermal conductivity q = -k (dT/dY)The Attempt at a Solution While this is quite an easy question, I just want to verify that I'm doing it correctly. Would it be correct to begin at the bottom of the rock layer...

Homework Statement A 20 kg rock falls with the force of gravity acting on it. Another force acts on the rock (same direction as gravity) that is proportional to the velocity squared, 100v^2. Come up with an expression of the rock's velocity at any time t. Homework Equations Hint...