Rock Definition and 351 Threads

A uniform meter stick supported at the 25-cm mark is in equilibrium when a 1-kg rock is suspended at the 0-cm end. Is the mass of the meter stick greater than, equal to, or less than the mass of the rock? Explain your reasoning. Thanks in advance for any help!

Is it possible to have friction between clothing and a giant rock equal to 833 N? The μ would equal 4.58. Isn't it too big?

Homework Statement Geologists are able to calculate ages of rock samples through measurements of certain isotopic rations combined with known radioactive decay rates (all such decays being considered to adhere to 1st order kinetic rate laws). Two such processes leading to stable isotopes are...

Homework Statement I was tutoring the other day, when we came across a problem that had me stumped! A person standing on a hill that forms an angle \theta = 30^o wrt to the horizon, throws a stone at {\bf v} = 16 m/s up the hill at an angle \phi = 65^o wrt to the horizon. Find y_f...

Homework Statement A rock is thrown off a 100 m cliff at an angle of 38 degrees below horizontal with an initial velocity of 20.0 m/s. a) What is the total time in flight? b) What is the horizontal range? c) What is the max height reached by the rock? Homework Equations x = x_0 +...

Homework Statement A man drops a rock into a well. He hears the sound of the splash 3.2 seconds after he releases the rock from rest. The speed of sound in air (at the local ambient condition) is 338 m/s (a) How far below the top of the well is the surface of the water? (round your...

If a rock is thrown horizontally from a cliff at 25 m/s, what will its velocity be (magnitude and direction) after 3.0 seconds. The answer is 38.6 m/s, and 49.6 degrees down, but I cannot figure out how to get to it. Not sure which equations to use, I just started and I am learning on my...

If a rock is sinking in water with constant speed.. how many forces are working on it?

The laws of motion -- rock sliding on a roof Homework Statement One side if 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 15ms-1.The...

Hello, Homework Statement You throw a 0.500 kg rock underhand, as shown in the diagram. The rock starts at rest from the lowest point moving at an angle of 40° above the horizontal, and leaves your hand 0.300 s later having traveled 1.20 m. What is the average force that you exert on the...

Homework Statement A rock is thrown down off a cliff at 18 m/s at an angle of 17 below the horizontal. If the rock hits a cliff that is 16m away, how far down did the rock fall. Homework Equations Vf= Vi + at change in Y= Vit + .5at^2 The Attempt at a Solution I tried solving for...

Homework Statement A stone is thrown horizontally from a height h above the ground (h > 0). The stone hits the ground after having traveled a horizontal distance x (x > 0). What is the expression for the initial speed v of the stone? Neglect air resistance. (please use the variables x and h...

You are climbing in the High Sierra where you suddenly find yourself at the edge of a fog-shrouded cliff. To find the height of this cliff, you drop a rock from the top and 8.50s later hear the sound of it hitting the ground at the foot of the cliff. Ignoring air resistance, how high is the...

Homework Statement Assuming that the rock launched by a catapult is released from ground level, show that the theoretical maximum range is: R=2Mh/m, where M = mass of counterweight m = mass of rock h = height counterweight falls Homework Equations Ep=mgh Ek=(mv^2)/2 The Attempt...

Homework Statement A boy throws a rock at speed v_0 at angle α from a balcony of height h. When the ball hits the ground, its velocity makes an angle θ with the ground. What is the minimum value of θ in terms of h and v_0 Homework Equations basic kinematics equations. The...

I understand that when chondritic material is heated, the first material to melt is matte - eutectic mixture of troilite with a small excess of iron-nickel. This melts at about 990 Celsius. At this temperature, most silicate minerals are still solid. And so is nickel-iron, which needs over...

Homework Statement You are videotaping a birthday party in your dorm room; your dorm window in centered in the frame of your video camera. Suddenly, a rock passes by your dorm window! Assuming the rock was thrown horizontally, and assuming that the rock was traveling in a plane parallel to...

1. Homework Statement : A rock of mass m is attached to a string of negligible mass and length L. The rock is released from rest from a horizontal position. When the rock is at point P, the string attached to the rock makes an angle θ with the horizontal. In terms of the quantities, m, L, θ and...

I'm a Junior, about to be a Senior, majoring in Physics at a California State University. I am terrified about my career prospects. I am a fairly good student (3.5 GPA) and really love physics. I've taken Quantum I, Modern Physics, Thermodynamics and a couple E&M classes and I have enjoyed...

Homework Statement A Rock is dropped from a cliff and the sound of it striking the ocean is heard 3 seconds later. If the speed of sound in air is 340m/s, how high is the cliff? Homework Equations The linear kinematics of motion equations: 1. x-x_{0}=v_{0}t+\frac{1}{2}at^2 2...

1. A rock is dropped off the top of a building. On the way down, the rock passes a window. The window is known to be tall and the stone takes 0.154 to fall past the window. 1. What is the velocity of the rock at the bottom of the window? 2. How much time was necessary from the instant the rock...

Homework Statement A rock is dropped off the top of a building. On the way down, the rock passes a window. The window is known to be 2.00m tall and the stone takes 0.164s to fall past the window. 1)What is the velocity of the rock at the top of the window? 2)What is the velocity of the...

The windshield of a car has a width of 1067mm and a height of 889mm. The windshield also has a crack with a length of 305mm and a height of 1mm. What is the probability of a rock, with a random trajectory and a measurement of 1mmx1mm, hitting the windshield strikes directly in the center of the...

This was the sub-forum where I thought I may be able to find any help in, so I really hope I didn't go wrong there. So, dear readers, I come to you because I have ran out of options to get me out of the mess I find myself to be in right now. If you could lend me your honest thoughts and advice...

"A 2kg rock is suspended by a massless string from one end of a 1m measuring stick." 1. "A 2kg rock is suspended by a massless string from one end of a 1m measuring stick. What is the mass of the measuring stick if it is balanced as shown below." ______________ |___|___|___|___| M...^ ...^^...

Homework Statement A sling shot can launch a 50gram rock at a speed of 24m/s if it is stretched .4meters before release. Find the average force applied to the rock Homework Equations Spring force = 1/2*k*x^2 1/2kx^2 = 1/2mv^2 The Attempt at a Solution tried to solve for K...

Homework Statement A 8.00 kg stone lies at rest on a spring. The spring is compressed 10.0 cm (.1 m) by the stone. What is the spring constant? Homework Equations F = -kx E = (1/2)kx^2 U = mgh The Attempt at a Solution The solution provided uses a net force equation balancing Hooke's...

Homework Statement In Robert Heinlein's The Moon is a Harsh Mistress, the colonial inhabitants of the moon threaten to launch rocks down onto Earth if they are not given independence (or at least representation). Assuming that a gun could launch a rock of mass m at twice the lunar escape...

Homework Statement A man on a boat throws behind him a rock of mass m1=2kg with a velocity of v1=18m/s. The mass of a man with a boat is m_2=90kg. What velocty v_2 will the boat go with? Homework Equations v2 = (m1*v1)/m2 The Attempt at a Solution So I was upsent on the lesson...

Homework Statement A rock was thrown at the angle of 30 degrees against the horizontal surface, being given a velocity V_0=12m/s. Find the largest height h and the Z - the range of the throw. Homework Equations h_{max}=\frac{v_0^2\cdot\sin^2\alpha}{2g} Z=\frac{v_0^2\cdot\sin...

Homework Statement You drop a rock(from rest) into a well. You hear the rock hit the bottom 3.15 seconds after you dropped it. How deep is the well? Do not ignore the time for sound to travel back up to your ear. Velocity of sound = 343 m/s (constant), g = 9.8 m/s^2 Homework Equations...

Homework Statement It has been suggested, and not facetiously, that life might have originated on Mars and been carried to Earth when a meteor hit Mars and blasted pieces of rock (perhaps containing primitive life) free of the surface. Astronomers know that many Martian rocks have come to...

A number of people have said they are interested in this topic. Please posts any pictures, information or questions about rocks or fossils here. I'll start off with some odd formations in rock here from the Pennsylvanian period (318.1 to 299.0 mya). They appear to be strips of wood, but...

Homework Statement 1. You stand on a spring-loaded bathroom scale in a bathroom. The scale "reads" your mass. What is the scale actually measuring? 2. Similarly, you stand on a spring-loaded bathroom scale in an elevator that is accelerating upward at 2.0 m/s^2. The scale "reads" your mass...

Homework Statement A rock dropped from a cliff covers one-third of its total distance to the ground in the last second of its fall. Air resistance is negligible. How high is the cliff? Homework Equations v = v0 + at2 h = v0t + 0.5at2 v2 = v02 + 2ahh = distance in this case The Attempt at a...

When is it energetically favourable for a piece of rock to crumble into two pieces? I couldn't paste latex code here for the life of me so I attached a pdf containing my calculation. It is obviously wrong because it leads to the fact that a box-shaped rock of height sqrt(2) (say meters) would...

Can anyone answer a couple of questions about the new floating rock raft off New Zealand ? How much mass does it contain ? Where is it headed ? ( or will it disperse ? )

Homework Statement Container filled with water is placed on a scale. case #1 Lid is closed. Rock is placed on top of the lid. case #2 Rock is placed inside the water container, it sinks to bottom. Lid is closed. How does the weight (reading on the scale) compare in the two...

In a rock tumbler, the stones collide with each other and break apart. Eventually they become smooth. I was thinking about exchange of energy like when billiard balls hit. When two billiard balls collide, they exchange their energy. It's a little different if they have different amounts of...

Hey Guys, I have a problem I am working on and was wondering if someone could point me in the right direction. The problem: I need to calculate a force to apply to a given area of the front of a vehicle in relaticely small collision / impact with both a stationary and possibly a small...

I would not have recognized many of them. http://www.nbcsandiego.com/entertainment/music/NATLRock-Stars-Then-and-Now-97329329.html

Homework Statement so there's a 6 kg rock spinning in a circle with a string that can with stand a maximum tension of 75 and a radius of 1.5m and i need to find the maximum speed before the string will breakHomework Equations Fnet=ma a=4\pi2R/T2 The Attempt at a Solution so Fnet =ma and a =...

A 70kg climber is dangling over the edge of an ice cliff. He is roped to a 940kg rock located 51 m from the edge. The ice is frictionless, and the climber starts to accelerate downward. a) How would you find the acceleration of the climber? Would you use the force diagrams for the rock and...

A 70kg climber is dangling over the edge of an ice cliff. He is roped to a 940kg rock located 51 m from the edge. The ice is frictionless, and the climber starts to accelerate downward. a) How would you find the acceleration of the climber? Would you use the force diagrams for the rock and...

Homework Statement A vibration platform oscillates up and down with an amplitude of 10.4 cm at a controlled variable frequency. Suppose a small rock of unknown mass is placed on the platform. At what frequency will the rock just begin to leave the surface so that it starts to clatter? Homework...

Homework Statement A hiker throws a stone from the upper edge of a vertical cliff. The stone ' s initial velocity is 25.0 m/s directed at 40.0 degrees with the face of the cliff, as shown in Fig. 3.1. The stone hits the ground 3.75 s after being thrown and feels no appreciable air resistance...

Homework Statement I have been given this example with the following questions: 1. Two rocks are thrown off of a cliff with the same initial speed, v. The first rock is launched with at an angle Ө directed below the horizontal as shown below as 1, while the second rock is launched above at the...

Since it has a decimal it would be 20kg * 9.8m/s which equals 196kg m/s^2 = 196N But the decimal means i have to round two sig figs, which would make it 200N? A very simple problem, I really don't know why I'm asking it.

Homework Statement A rock is thrown vertically upward with a speed of 17.0 from the roof of a building that is 60.0 above the ground. Assume free fall. In how many seconds after being thrown does the rock strike the ground? Homework Equations I used v^2 = vinitial^2 + 2a(y - yinitial)...

Homework Statement Rock A is thrown straight up from the top of a 25m tall building at a speed of 20m/s. Exactly 1 second later Rock B is thrown in such a way that it lands on the ground at the base of the building at the same instant that Rock A lands. What is the initial velocity for Rock...