Newtons Definition and 494 Threads

I having a little trouble grasping the 3rd law because of this idea in my head about a situation where a large truck going very very fast hits a person standing still. 1)Lets say the truck is going fast enough where the person's body will slightly rupture due to the impact. How can that tiny...

Homework Statement I'm in high school and I haven't taken physics yet, but I'm doing a science project where I'm comparing a space shuttle liftoff to a liftoff using a magnetic field created by coils. I found the force that the space shuttle uses at liftoff and now I have to scale it down...

Homework Statement mv'=-gm-kv Find the position function using the initial coniditions of t=0 for all Constants Homework Equations Reverse product rule The Attempt at a Solution My attempt is on my white board. Its attached as a picture.

Three blocks, each of mass 7.0 kg are on a frictionless table. A hand pushes on the left most box (A) such that the three boxes accelerate in the positive horizontal direction as shown at a rate of a = 1.1 m/s2. What is the net horizontal force on block B? =15.4 N What is the horizontal...

Homework Statement On the earth, an astronaut and the equipment weigh 1,960 N. Weightless in space, the motionless astronaut and equipment are accelerated by rocket pack with 100 N thrust, that fires for 2.0s. What is the resulting final velocity? (Hint: First calculate the acceleration...

Hi there can anyone please explain to me these questions I am really confused about them. Q: A 15 kg wagon is pulled to the right a force of 45 Newtons. the wagon accelarates at 2 m/s2. what is the net (unbalanced) force accelerating the wagon? (f of g is 10) the book says the answer is...

Homework Statement two questions below in my classical mechanics course (our first homework assignment) and I'm not sure what the questions are actually asking...do they want the equations? descriptions of the laws? names of the laws? I'm confused because question one and two seem very...

We have a Newtons cradle , when you let go of one ball at one end you know what happens. Rlease one ball and the other side has a ball osciallte. But if you release two balls (with a 5 ball cradle) , why is that two balls on the other side of the middle ball also rise in response. How does...

Homework Statement Let e be the number close to sqrt(a) by Newtons Method (That is picking a number, diving a by it, and taking their average, divide a by average, get a number, find their average, so on). Using |e<sqrt(a)+e| prove that if |a/e-e|<1/10 then |sqrt(a)-e|<1/10 Note that e is...

Homework Statement A shell is fired at an abgle of 30 degrees to the horizontal. If the shell stays in the air for 40 seconds, calculate a)how far it lands from it's original position b)the highest point it can reach Homework Equations N/a The Attempt at a Solution I was...

Homework Statement A comet is affected by a gravitational force due to the presence of the Earth. Later, the comet is ten times farther from the Earth. What is the size of the new gravitational force acting on the comet? a) One hundred times larger than before. b) Ten times larger than...

Homework Statement Please help I'm terrible with physics =[ 1) If r is the radius of the Earth, how far above the surface of the Earth would you have to go so that your true weight is one-fourth of what it is on the surface of the Earth? a) r b) 2r c) 3r d) 4r The only formulas I was given...

I've attached an image explaining the problem. All pulleys are massless. Basically, they want me to show some relations between wire tensions, using Newtons 2nd law for rotational motion. This law is written in my book as: dL / dt = torque, where L is angular momentum. I'm not sure...

A 2.5 kg mass accelerates at 6.1 m/s in adirection 37◦north of east. One of the two forces acting on the mass has a magnitude of 6.05 N and is directed north. Determine the magnitude of the second force. Answer in units of N I know you have to break it up into multiple components, but otherwise...

Newtons Rings Calculations - Values Not Working Out I'm having trouble with a Newtons Rings experiment to determine the refractive index of water. I'm using a sodium light source and a Vernier scale traveling microscope to measure the radius of the bright circles (I don't know if measuring the...

Homework Statement The Plateau equation (minimal surface of a soap film) can easily be derived from variational principle. We want to minimize the area of the soap film, S = \int \sqrt{1 + z_x^2 + z_y^2} \, \mathrm{d}x \, \mathrm{d}y , and through Euler-Lagrange equation we get the...

Homework Statement A 2.5 kg mass is attached to a 3.5 kg mass by a light string that passes over a friction-less pulley. The masses are released. a) What is the magnitude of the acceleration of the masses? b) What is the tension in the string? Homework Equations (I think) Ft - mg = ma The...

Homework Statement Why when I convert kg to Newtons I simply multiply by g. But when I convert lbs I multiply by 4.48?? It makes no sense ! Shouldn't it be 32.2? Thanks, Kate Homework Equations The Attempt at a Solution

Homework Statement Homework Equations Newtons' Laws Kinematics Equations The Attempt at a Solution I don't know what I'm doing wrong, but I'm not getting the correct answer of 17cm ... :cry:

Im makeing a hydro gravity genoratetor I need to no how much air to release to give 800w

Homework Statement You have a fuzzy dice with mass .2kg hanging from the rear view mirror. When you step on the gas the dice makes an angle of 25 degrees. what is car's acceleration? Homework Equations F=ma...? Fr=mac..? The Attempt at a Solution Im really not sure where to start...

Homework Statement A gardener pushes down on the handle of a lawnmover, applying a force of 250N. The handle is inclined at an angle 45* to the horizontal. If the coefficient of the kinetic friction between the wheels of the lawnmower and the ground is 0.40, what is the acceleration of the...

I've always had some trouble with these terms and using them interchangeably but I feel like I've finally made the clarification for myself. In the most rudimentary terms, it seems that the mass of something is the amount of "stuff" occupying it, whereas weight is the force of gravity on...

Just a problem for my physics homework and just wondering how to solve this problem.

I would like to know how much of a % does Newtons 3rd law (action / reaction) account for lift of a chopper.. i would also like to know this for Bernoulli's principle.. Can you give a source to back it up? I can't find an answer any where

Sometimes I wonder if it actually possible to prove the action-reaction principle. I do know that Newtons laws are empirical but then if you think about the third law it says that in interaction between two bodies they exert equal and opposite forces on each other. Now what happens in the...

Is shown like this in my book: Consider a rotating body with an angular acceleration α. There must be a tangential force component if it is rotating: For a general point on the body we can write: Ftan = mi * ai = mi * ri * α (1) Multiply by ri and sum up you...

Please anybody explain me ... if i punch a soft cushion hardly say "F" force will thw cusion hurt me with the same ... every body says "NO" ok all right everybody says "you, in this case have not applied the "F" force because most part of it is wasted in changing the shape of cusion " so here...

Homework Statement The static friction between the two blocks is .47 and kinetic friction between the block with mass 9.4 kg and the horizontal surface is 0.21.The acceleration of gravity is 9.8 m/s^2 What is the minimum force F which must be exerted on the 9.4 kg block in order that the 0.8...

I know that Newtons law of cooling is useful when a solid is transferring heat to a fluid. And conduction equation is used in solids. My question is: 1) Can Newtons law of cooling be applied in case of solids (apart from Heat conduction equation)? 2) Can Newtons law of cooling be applied in...

Hello, Is there any research available as to whether Newtons Law F = mg should include horizontal surface area as a factor (ie the surface area of opposing masses). Example a pole weighing exactly the same seems heavier when held at one end horizontally to the ground, compared to holding it...

Homework Statement http://www.lhup.edu/~dsimanek/scenario/Newton.htm This is a good animation of how Newton's Cradle works There was a question in an exam paper, Ed Jan 2011. A student obsereved that when the raised ball collided weith the nearest stationary ball and stops. The ball...

Homework Statement please i need help as have been trying to solve this question: A body cools from 70°C to 50°C in 6mins when the temp of the surrounding is 30°C. what wil be the tempt of the body after another 12mins if the cooling obeys Newtons law of cooling equation: dq/dt =...

"Simple" Newtons laws question ? At time t = 0 a particle of unit mass is projected vertically upward with velocity v_0 against gravity, and the resistance of the air to the particle's motion is κ times its velocity. Show that during its flight the velocity v of the particle at time t is...

Homework Statement An elevator containing 3 passengers(with a mass of 72kg 84 kg and 35 kg) has a mass combined of 1030 kg . The cable attached to the elevator exherts an upward force of 12000 N. But the friction opposing the motion of the elevator is 1400 N. a) Draw a free body diagram...

Homework Statement I just wanted to know if I was correct, when dealing with a Newton law problem that has components. Ʃfx=0 and ƩfY = zero However when we add the forces together then we can use Ʃf=ma thanks Homework Equations The Attempt at a Solution

1)A rock is dropped off a cliff and falls the first half of the distance into the ground in t1 seconds. If it falls the second half of the distance in t2 seconds, what is the value of t2/t1? Relevant equations: I think the kinematics equations of d=vt+(1/2)at^2 I have no idea how to solve...

1)A rock is dropped off a cliff and falls the first half of the distance into the ground in t1 seconds. If it falls the second half of the distance in t2 seconds, what is the value of t2/t1? Relevant equations: I think the kinematics equations of d=vt+(1/2)at^2 I have no idea how to solve...

I know this is just a piece of whining, but I feel awful about it and want other's opinions. It wouldn't really bother if I didn't think I'm OK in physics. In a question I had to calculate potential energy and naturally wrote the answer down as joules. However, when I came back to check the...

Homework Statement I've attached the questionHomework Equations x(n+1) = x(n) - f(x(n)) / f '(x(n))The Attempt at a Solution okay so x2= 1.3517323300 and I've already calculated x3 to be 1.3483949227 then how do i estimate the error in x2? do i subtract or something?

Homework Statement I've attached the question Homework Equations x(n+1) = x(n) - f(x(n)) / f '(x(n)) The Attempt at a Solution 2.5x^3 =2cos(x) + 8 okay so this has to be in the form of f(x) = ... but there is no y variable for me to make it into that form. once I've gotten it into...

Whats more basic - Newtons third law or conservation of momentum You can prove Newtons third law by conservation of momentum but you can also prove conservation of momentum by Newtons third law. What comes first?

Application of Newtons laws (Friction related) check my solutions please :) Dont forget to check the diagram, as it will probably help you see the problem correctly, don't worry, no need to download diagram attachment to view it. Homework Statement A child pushes a block of wood with a...

Hey guys, need some help with this question. I am stuck and don't know what to do. Q: Show that using Newton's method to $$1-\frac{R}{x^n}$$ and to $$x^n-R$$ for determining $$(R)^{\frac{1}{n}}$$ results in 2 similar, but different iterative formulas, with $$n \ge 2$$ and $$R >0$$ Thanks for...

A man sits in a seat that is suspended from a rope. The rope passes over a pulley suspended from the ceiling, and the man holds the other end of the rope in his hands. What is the tension in the rope and what force does the seat exert on the man? Draw a free body for the man. The tension...

Hey, I'm trying to figure out how to do Newtons method in 2 dimensions. That is, I want it to take in an input of my initial matrix {x0,y0} and then follow the algorithm to find the solution to f1(x,y)=0, f2(x,y)=0. The algorithm is {x1,y1}={x0,y0}-A^-1*F{x0,y0} where A is the matrix of mixed...

Homework Statement A 245 kg motorcyle & rider can produce an acceleration of 3.50 m/s sq while traveling at 25 m/s. At that speed, the forces resisting motion (friction & air) total 400 N. What force does the motorcycle exert backward to produce it's acceleration? Homework Equations...

Newton`s first law states that an object will continue to remain in its state of rest or motion with uniform velocity unless and until acted upon by a net external force. Newton`s second law F=ma In this equation if F=0 then a=0 that is the same as the first law... So, if the first law is a...

Homework Statement Hi In a book they state \frac{dv}{dt} = a \quad \Rightarrow \quad v(z) = \sqrt{2a(z-z_{max})} I am trying to reproduce this. Here is what I have so far: dv/dt = (dv/dz)(dz/dt) = v(dv/dz) = a Since a is constant (I assume?), I get \int vdv = \int adz \quad...

Homework Statement A car travels on a horizontal street, straightforward. In some moment of time (t = 0), having a velocity of 20 m/s, the break is hit. It is required to find the time and traveled distance before the car is still standing. The friction coefficient between the wheels and the...