Rock Definition and 347 Threads

Roshambo is the name for a popular two-person hand game. It may also be referred to as Paper, Rock, Scissors. Rock blunts scissors, scissors cut paper, paper folds around rock. Nature plays it too. But instead of paper it uses logs: Log folds around rock...

How would I go about deriving the cooridinate numbers of both ions in rock salt, and, how could I account for the differences in lattice enthalpy between the following; LiCl (861 kJ/mole) - NaCl (787) LiCl - LiF (1046) LiCl - MgO (3850) Cheers.

Here is the Problem. A 2.8-kg block slides over the smooth, icy hill shown in the figure .The top of the hill is horizontal and 70 m higher than its base. i attached the Figure Below. What minimum speed must the block have at the base of the hill so that it will pass over the pit at the far...

Homework Statement Bob can throw a 620g rock with a speed of 30m/s. He moves his hand forward .8m while doing so. a.) How much work does Bob do on the rock? b.) How much force, assumed to be constant, does Bob apply to the rock? c.) What is Bob's maximum power output as he throws the...

A rock of mass 200g is attached to a 0.75m long string and swung in a vertical plane. A) what is the speed that the rock must travel so that its weight at the top of the swing is 0? B) what is the tension in teh string at the bottom of the swing? C) if the rock is now moved to a horizontal...

A friend and colleague found a fossil and brought it into show me. It is a small leaf in a rock. He asked me how the rock was formed, but I couldn't say as I know nothing of such things. The rock is layered. You can see the various layers by looking at the rock edgewise. In fact, the edge is so...

A rock hound finds a solid rock that contains only quartz and gold. The rock has a mass of 12.08 kg and a volume of 3.909×10-3 m^3. What is the mass of the gold contained in the rock? Density of gold: 19300 kg/m^3 Density of quarts: 2660 kg/m^3

A rock of mass 200g is attached to a 0.75m long string and swung in a vertical plane. A) what is the speed that the rock must travel so that its weight at the top of the swing is 0? B) what is the tension in teh string at the bottom of the swing? C) if the rock is now moved to a horizontal...

Homework Statement A catapult on a cliff launches a large round rock towards a ship on the ocean below. The rock leaves the catapult from a height H of 33.0 m above sea level, directed at an angle θ above the horizontal with an unknown speed v0 The projectile remains in flight for...

Homework Statement Bob, who has a mass of 85 kg, can throw a 450g rock with a speed of 30m/s. The distance through which his hand moves as he accelerates the rock forward from rest until he releases it is 1.8m. a.) What constant force must Bob exert on the rock to throw it with this speed...

Homework Statement Imagine a climber 5.00 m directly abour her uppermost piece of protection, with no slack (exercise lenght) in rope, and the next piece of protection is 6.00 m directly below the uppermost piece of protection. She falls with an acceleration of 9.80 m/s^2 downward. The first...

Homework Statement A soccer player kicks a rock horizontally off a 40.0-m-high cliff into a pool of water. If the player hears the sound of the splash 3.00s later, what was the initial speed given to the rock? Assume the speed of sound in air to be 343 m/s. Homework Equations Well to...

Homework Statement 1. A person throws three identical rocks off a cliff of height h with exactly the same speed v0 each time. Rock A is thrown vertically upward, rock B is thrown straight out horizontally, and rock C is thrown straight downward. If we ignore the effects of air resistance...

A small but amazing set of pictures for this contest. Please vote for the picture that best represents our theme, which are on boats and other floating vessels. 1. dontdisturbmycircles http://img120.imageshack.us/img120/9024/p1000654jx5.jpg 2. siddharth 3. ZapperZ 4. George...

I don't know much about classical physics, if I throw a rock or mass M upward with an initial velocity Z, with gravity g and air resistance A acting against it, is this equation the right one ; m\frac{dv}{dt} = (Z-g)m -Av Then if I want to know the maximal height, I just need to integrate...

Due to popular demand, our PF Photo Contest is BACK starting this week. All the rules are the same as before. [FONT="Comic Sans MS"]Rock The Boat The theme this week involves boats and other floating vessels. It includes ocean liners, powerboats, sailboats, kayaks, barges, and dinghies...

kicking rock of a building... Homework Statement A boy kicks a rock at a velocity of 19.8 m/s horizontally off the top of a 64 meter high building. How far from the top does the rock hit the flat ground? (neglecting air resistance) Homework Equations sorry, i don't know how to type...

Homework Statement A climber of mass 72 kg can stand on a rock sloping at 40degrees to the horizontal. What can you deduce about the coefficient of static friction between his boots and the rock? ________________________________________________________ I'm really lost on this one. His...

A bridge rises 321m above the Arkansas river. Suppose you kick a rock horizontally off the bridge. The magnitude of the rock's horizontal displacement is 45.0 m. Fine the speed at which the rock was kicked. (This is not what i ask you here) Does the ball travel 321m vertically in free fall...

A rock with a volume of 0.2m3 is fully sumberged in water with density of 1000kg/m3. What is the buoyant force acting on the rock? Assume that gravity acts on the system 0.2m3*9.81m/s2 = 1.96 buoyant force = 1000kg/m3*1.96 = 1960N ?

[b]1. You are standing on the edge of a ravine that is 11.5m wide. You notice a cave on the opposite wall whose ceiling is 6.4m below your feet. The cave is 4.7m deep, and has a vertical back wall. You decide to kick a rock across the ravine into the cave. 1. What initial horizontal velocity...

Since a rock has gravity, doesn't a rock have energy within it? Are there bonds caused by energy at the atomic level within a rock?

Homework Statement A catapult on a cliff launches a large round rock towards a ship on the ocean below. The rock leaves the catapult from a height H of 32.0 m above sea level, directed at an angle q above the horizontal with an unknown speed v0...

a rock is thrown from the tope pf a 20m buliding at an angle of 53 deg. above the horizontal. of the horizontal range of the throw is equal to the hieght of the buliding, with what speed was the rock thrown? if i am given range i am trying to use x=xo+vot+.5at^2 but i don't know the time...

Homework Statement A rock of mass 5.5kg is hanging from the ceiling moving in uniform circular motion. The radius of the orbit is .8m. The angle of the rope in comparison to if it were hanging straight down is 15 degrees outward. What is the magnitude of the force of the cord on the...

A rock is thrown from the roof of a building with a velocity v_0 at an angle of alpha_0 from the horizontal. The building has height h. You can ignore air resistance. Calculate the magnitude of the velocity of the rock just before it strikes the ground. Homework Equations V=V_0 + at...

Homework Statement A rock is dropped from a sea cliff, and the sound of it striking the ocean is heard 3.2s later. If the speed of sound is 340 m/s, how high is the cliff. Homework Equations d= v1t + 1/2at^2 v2^2 = v1^2 + 2ad The Attempt at a Solution I tried using d = vt...

Homework Statement - A guy sees a rock falling from a plateau. He estimates the last third (1/3) of the rocks fall to last for 1,3 sec. Air resistance doesn't need to be taken into consideration. - How far/what distance has the rock fallen? Homework Equations None given The...

Applying Newton's Laws With Rock Climbing How Would You Apply Newton's Laws With Rock Climbing? ?

Homework Statement Someone places a 6.0m long steel rod on a rock so that one end is under a baby moose weighing 2.0 kN. THe person pushes down on the other end of the rod with a force of 400N, and the moose is held in the air at rest. The rock was: (a) 1.0m from the moose (b) 5.0m from the...

k in my advanced physics class 32S we are doing a project on buoyancy, one of the questions we have to answer is if you go out in a pool in a boat with a rock in it, then you throw the rock over board will the water level go up/down/stay the same. I am pretty sure that the water level will go...

rock on a string on the ceiling??! I'm stuck on this problem... any ideas?? A stone hangs by a fine thread from the ceiling and a section of the same thread dangles from the bottom of the stone. If a person gives a sharp pull on thedangling thread, where is the thread likely to break: below...

An 8.00 kg stone rests on a spring. The spring is compressed 7.0 cm by the stone. (a) What is the spring constant? 11.2 N/cm (b) The stone is pushed down an additional 30.0 cm and released. What is the elastic potential energy of the compressed spring just before that release? 76.7 J...

"On the moon of a distant planet, an astrnaut measures the period of a simple pendulum, 0.85m long, and finds it is 4.7 seconds. Back on Earth, she could throw a rock 13m straight up (while wearing her spacesuit). With the same efoort, how far up can she throw the same rock at her present...

A geologist finds that a moon rock whose mass is 7.85 kg has an apparent mass of 6.18 kg when submerged in water. What is the density of the rock Would I use pressure to solve for the mass of the moon rock?

This is the problem: You throw a 20-N rock vertically into the air from ground level. You observe that when it is 15.0 m above the ground, it is traveling at 25.0 m/s upward. Use the work-energy theorem to find a) its speed just as it left the ground; b) its maximum height. I drew a...

*4. 23) A soccer player kicks a rock horizontally off a 40.0 m high cliff into a pool of water. If the player hears the sound of the splash 3.00 s later, what was the initial speed given to the rock? Assume the speed of sound in air to be 343 m/s. What I did: Again I drew a diagram. I...

to any and all the player

Hi, A rather simple question that I just can't seem to solve: The greatest instantaneous acceleration a person can survive is 25g, where g is the acceleration of free fall. A climber's rope should be selected such taht, if the climber falls when the rope is attached to a fixed point on a...

Life exisits on the third rock, maybe because of some exquisitve tuning of cosmological parameters, or maybe it is just a fact, so far life on the third rock is unique, so how safe is this (fact) (chance), given that migration to other planets is far in the future, what chance does life have...

In Figure 12-38, a 50 kg rock climber is in a lie-back climb along a fissure, with hands pulling on one side of the fissure and feet pressed against the opposite side. The fissure has width w = 0.20 m, and the center of mass of the climber is a horizontal distance d = 0.40 m from the fissure...

I think it is safe to say that all musical talent in the United States has been exausted. I just watched Conan and the musical "talent" for the show was a band called "Be your own pet". This was not music. This could not be construed to be music either. No human being on this planet with ears...

http://abcnews.go.com/US/story?id=2050910 :smile:

Hello, if someone could help me with the second part of this problem, I would be so grateful. A rock is tossed straight up with a velocity of + 20 m/s When it returns, it falls into a hole 10 m deep. What is the rock's velocity as it hits the bottom of the hole? I got -24.4 m/s for...

Congrats to Finland and Lordi to their first victory in the Eurovision Song Contest!:biggrin: :biggrin: :biggrin: I don't even know what to say about the performance...:biggrin: :eek: :-p http://eurovision.lordi.org/ http://www.eurovision.tv/english/index.htm http://www.lordi.org/

I have often seen arguments like these by people who claim that they have disproved the existence of God. Either answer would mean that God is not omnipotent and therefore cannot exist. Now I am an atheist. Is there any merit to the above argument?

I have equations for the following problem and an answer, but I am not sure if they are correct: Suzie (a geology student) is attacking a police van during a demonstration for peace and love at the University. The van is escaping at 3.2 m/s. Suzie throws her rock when the back of the van is...

A 52 kg rock climber is climbing a “chimney” between two rock slabs. The coefficient of static friction between her shoes and the rock is 1.33; between her back and the rock it is 0.89. She has reduced her push against the rock until her back and her shoes are on the verge of slipping. (a) What...

I rather liked https://www.physicsforums.com/showthread.php?t=110807", and thought it had potential (for imagination that is - HINT HINT :rolleyes:), but it was shut down when it became too silly. With Evo's permission (granted), and Mattara's permission (pending), I'd like to start it again...

Hi Everyone! I've been working on this Physics problem for the last week and I still can not figure it out! I'm sure I'm missing some very basic concept, but I'm not sure how to proceed: An Australian bushman hunts kangaroos with the following weapon - a heavy rock is tied to one end of a...