Second law Definition and 479 Threads

Homework Statement Two calibrated elevation blocks have a combined thickness of 1.86 cm. Find the angle of elevation of the 1.00-m long track for this situation. Homework Equations F = ma? The Attempt at a Solution I'm having a LOT of trouble, even beginning to draw the picture for...

Homework Statement When a horizontal force F is applied to a box having a mass m, the box sides on a level floor, opposed by a force of kinetic friction f. a. What magnitude of acceleration occurs for the box? b. Calculate the acceleration if the horizontal force is 412N, friction is...

The second law of thermodyanics states that heat cannot flow from a colder region of space to a hotter region; When you open a door that previously separates your warm house from the cold outside; What substance/process is flowing then to drive the heat out of your warm house to make your...

Homework Statement Imagine that there is a slab (call it block 1) on top of which sits a block (call it block 2). The slab connects to a cable that passed through a pulley and attaches to another block (call it block 3), hanging freely. Assuming that the coefficient of kinetic friction is...

This is not a homework problem so I am ignoring the template. I was watching Walter Lewin's video lectures and this experiment he performs intrigues me. I have given it a thought for over an hour but have no answer as to which and why will that string break. I have uploaded the experiment...

According to Newton's second law, how are acceleration and mass related? Directly or indirectly when force is constant? I believe it indirectly. Am I right?

Thermodynamics makes good predictions for macroscopic experiments, but the actual physics is going on in the microscopic particular level. The second law of thermo is often thrown around, usually by people who couldn't explain F=ma back to you. My question is the way the second law...

Hi! Why is a in F=m*a equal to a =(d^2 x) / (d t )^2 and not to (d x)^2 / (d t )^2 Mark

Newton's second law is taking my mind for a spin and for some reason had me contemplating how it works for several hours. This is all with respect to an incline and an object sitting on the incline with no friction. If the problem does not give you the mass of the object can you completely...

the "d" in Newton's second law of motion? Hello there my fellow quantum inquisitors. I was just over in the physics forums library and was wondering what the "d" in the equations of Newton's second law of motion means? Thanks in Advance, ScienceNerd36.

Homework Statement Calculate the force needed to accelerate a 2.0kg ball at 3.0ms^2 (A) In space, a long way from Earth. (B) On a frictionless horizontal surface, near the surface of the earth. (C) vertically upward, near the surface of the earth.Homework Equations F = m*a The Attempt at a...

Homework Statement A triangle shaped moving block of mass M2 is pushed by force F , a block of mass M1 is on the other block, a)what should be the F force so that the block will be in rest relative to M2? b)what should be the Acceleration of M1 so that the block M2 will move up on the block...

Homework Statement Here is the question: http://img93.imageshack.us/img93/9159/snap1k.jpg Homework Equations First law: Q=W+U Second law: no thermodynamic system can convert heat into work 100%; heat flows from hot to cold reservoirs spontaneously; entropy always increases The...

Homework Statement A heat pump operates as an air conditioner, drawing 20000 Btu per hr from a building. It is operating between 21 degrees Celsius and 41 degrees Celsius. a) If the COP (coefficient of performance) is 35% that of a Carnot air conditioner, what is the value of the effective...

Homework Statement calculate the change of entropy (for the system) when 3 moles of a monatomic perfect gas, for which Cp,m = (5/2) R, is heated and compressed from 298K and 1atm to 398K and 5atm. ans: -22.1 JK-1 Homework Equations for an ideal gas, Pv=nRT for iso-choric condition...

As I understand it, the second law means that energy always tends to get delocalized. A blunt way to put it is that you can't make energy flow from a cold source to a hot one without doing work ( ie localizing a point by delocalizing another ) But here is an idea that struck me Suppose you...

Homework Statement We did something very similar to this in lab http://webenhanced.lbcc.edu/physte/phys2ate/2A%20LAB%20HANDOUTS/Moment%20of%20Inertia.pdf Use Newton's Second to derive the expression for the experimentally determined moment of inertiaHomework Equations Newton's Second Law is...

Homework Statement 1. Compare the mass of the system to the slope. Does your data support Newton's Second Law? 2. Using the words "directly" or "indirectly" briefly explain how force, mass, and acceleration are related to each other, making specific references to the parts of the...

Two blocks of identical material(Block1 20kg, Block2 10kg) are connected by a light rope on a level surface. An applied force of 55Nright causes the blocks to accelerate. While in motion, the magnitude of the force of friction on the block system is 44.1N. 2. Homework Equations...

according to Newtons second law: \vec{F}=\frac{d\vec{p}}{dt}=m\frac{d\vec{v}}{dt}+\vec{v}\frac{dm}{dt}(1) ie force impelled on a body is equal to the rate of change of momentum however when we use calculus to derive rocket equation we get: m\frac{d\vec{v}}{dt}={\vec{v}_{gas\; relative \;to...

Homework Statement A shell is shot with an initial velocity 0 of 29 m/s, at an angle of θ0 = 56° with the horizontal. At the top of the trajectory, the shell explodes into two fragments of equal mass. One fragment, whose speed immediately after the explosion is zero, falls vertically. How far...

Homework Statement Given a car being pushed by a constant force: a. How will the acceleration change in relation to the mass of the car? --> Done, it'll decrease b. How will a graph of acceleration in the y-axis and and (1/m) being the x-axis will look like? What will the slope of the...

Homework Statement A wagon carries a child. Together mass is 28.5kg. You pull on the handle of the wagon at an angle of 40degrees from the horizontal. The wagon travels over a level horizontal sidewalk. A force of friction of 12.0N acts on the wagon. a) What is the net force acting on the...

A wagon carries a child. Together mass is 28.5kg. You pull on the handle of the wagon at an angle of 40degrees from the horizontal. The wagon travels over a level horizontal sidewalk. A force of friction of 12.0N acts on the wagon. a) What is the net force acting on the wagon? Note...

Homework Statement A crate of mass 50.0 kg is pulled across a level concrete floor by a force of 300.0 N acting 30.0 degrees above the horizontal. The crate moves at a constant velocity of 0.962 m/s. What is the force of friction acting on the crate? Homework Equations SINE, COSINE...

Can gravity be expressed in terms of the second law of thermodynamics?

I have a question about Newton's Second Law and Inertial Frames of Refrence. It is canon that Newton's Second Law is only applicable in an inertial frame of refrence. Newton's Second Law is the net force acting on a body is equal to the time rate of change of the body's linear momentum...

Homework Statement True or false: "Torque cannot exist without a force acting on the body" Homework Equations t = force(rsin(theta)) The Attempt at a Solution I can't find a reason to believe the statement is false. Look at the equation: t = Frsin@, where the @ sin is theta, and F...

Homework Statement True or false: "Given that the same force acts on particle A and B, If object B covers the same distance in less time than particle A, object B is less massive than object A" Homework Equations net force = mass(acceleration) The Attempt at a Solution I believe...

Homework Statement I'd just like some verification really: see step three Homework Equations net force = 0 --> equilibrium; net force = ma The Attempt at a Solution I've come to the conclusion that the difference between Newton's first law and second law is acceleration...

A 4.0 kg block is put on top of a 6.0 kg block. In order to cause the top block to slip on the bottom one when the latter is held fixed, a horizontal force of 12N must be applied to the top block to overcome the maximum static friction. The coefficient of kinetic friction for all contact...

Homework Statement The 60 kg block starting at rest is pushed 7.8 m up a ramp at an angle θ = 26.5° to the horizontal in 15 s. If the coeficient of kinetic friction is 0.17: What is the acceleration of block? What is the force used to push the block up the ramp? Homework Equations Fnet...

Homework Statement Given data: - The weight of (A) is 3.6 N. - The weight of (B) is 5.4 N. - The kinetic friction coefficient between all surfaces is 0.25 http://img369.imageshack.us/img369/2999/figurehg3.png The problem statement: Find the required force for dragging (B) with a...

Homework Statement A 60.0 kg person stands on a scale in an elevator. (solve in Newtons) What does it read when the elevator is accelerating upward at 3.5 m/s2? What does it read when the elevator is accelerating downward at 3.5 m/s2? Homework Equations Fnet = ma The Attempt at...

Homework Statement As shown in the figure, a system undergoing a power cycle develops a net power output of 1MW while receiving energy by heat transfer from steam condensing from saturated vapor to saturated liquid at a pressure of 100 kPa. Energy is discharged from the cycle by heat transfer...

[b]1.Bsed on Newton's 2nd law,predict what will happen to the spaceshutter's acceleration after a lift as it burns its fuel Homework Equations F=ma The Attempt at a Solution since fuel is being burnt, thus mass of space shutter is decreasing as fuel is being burnt. force is...

Homework Statement A 50,000 kg locomotive is traveling at 60.0 when its engine and brakes both fail. How far will the locomotive roll before it comes to a stop? I'm completely lost and i don't know how to get started on this question

I'm not quite sure where to put this, in Physics or Biology. Mentors, please move this to the most appropriate location. A common argument put forth by creationists/intelligent design proponents is that evolution/abiogenesis violates the second law of thermodynamics, by causing a decrease in...

Homework Statement A space probe has two engines. Each generates the same amount of force when fired, and the directions of these forces can be independently adjusted. When the engines are fired simultaneously and each applies its force in the same direction, the probe, starting from rest...

ok, i need some serious help with Newtons second law. like i kind of understand it, but adding things like friction are giving me real problems. does anyone have any good resources or tips on how to understand/comprehend this? and i have a prolem: a man pushes a 15 kg lawnmower at constant...

Homework Statement Here's the question: An arrow, starting from rest, leaves the bow with a speed of 25.0 m/s. If the average force exerted by the bow were doubled, all else remaining the same, with what speed would the arrow leave the bow? Homework Equations F = ma The Attempt...

Heres the problem http://img141.imageshack.us/img141/2820/49686394mt3.jpg Now I have to work it out using Newtons second law and Work energy... For Newtons second Law (F = ma)...would I be using I = mk^2 M = I\alpha than setting up F = ma...? and for work energy I am...

Homework Statement A pulley, with a rotational inertia of 1.0 x 10^-3 kg*m^2 about its axle and a radius of 10 cm, is acted on tangentially at its rim. the force magnitude varies in time as F=0.50t + 0.30t^2, with F in Newtons and t in seconds. The pulley is initially at rest . At t=3.0 s...

Lubos has a posting today about how Lorentz violating theories of quantum gravity seem to imply violations to the second law of thermodynamics: http://motls.blogspot.com/2008/04/lorentz-violation-makes-perpetuum.html I don't quite understand the arguments, but e states that ``the second...

An important issue here. In 2001 Bojowald discovered that quantizing the basic (Friedmann) model of cosmology got rid of the classical singularity and typically replaced it by a bounce. A prior contracting phase leads up to the start of expansion. In the years that followed Penrose raised the...

[SOLVED] HW: Newton's Second Law and Angles Homework Statement The system shown in the figure can be used to measure the acceleration of the system. An observer riding on the platform measures the angle (theta) that the thread supporting the light all makes with the vertical. There is no...

The Problem: A 4 kg dog stands on a 16 kg flatboat at distance 12 m from the shore. The dog walks 5 m along the boat toward the shore and then stops. Assuming no friction between the boat and the water, find how far the dog is then from the shore. The dog's displacement is towards the shore...

Homework Statement Two objects of unequal mass are hung vertically over a frictionless pulley of negigible mass. Determine vector a1, vector a2, and the tentions. m1<m2 Homework Equations ΣFy=t-m1g=m1ay ΣFy=m2g-T=m2ay -m1g+m2g=m1ay+m2ay ay=m2-m1/(m1+m2)g The Attempt at a...

Hi I am going through an extreme headache trying to udnerstand the carnot engine and the second law of thermodynamics. To prove that the carnot engine (refreigerator engine) is the most efficient, my text included a prototype engine with a carnot refrigetrator together. So, the author says...

An object (mass 10.0 kg) slides upward on a slippery vertical wall. A force F of 60 N acts at an angle of 60 degrees (the force is 60 degrees South of the x+ axis, it's shown in a picture) Determine the normal force exerted on the object by the wall. Next, determine the object's acceleration...