Torques Definition and 101 Threads

Torques and Forces? I have found the first force,but I am not sure how to find the second :/. Two people sit in a car that weighs 8000N. The person in front weighs 700N, while the one in the back weighs 900N. Call L the distance between the front and back wheels. The person on the front is...

Does the line of a force applied need to go through the centre of mass to cause translational acceleration? I have follow up questions regarding the answer to this simple question which I can't find the answer for anywhere

A uniform girder weighing 700N is 3.0m long. It is placed horizontally on top of two narrow piers which is support it at points 30cm and 60cm respectively from its ends. Find the load carried by each pier.

Hello Forum, a sleeping top, rotating fast on its vertical axis, will resist small perturbation, small torque that try to move the rotation axis away from the vertical: if the top is moved a small angle away from the vertical, it will act so that the axis quickly returns to the vertical...

Homework Statement A traffic light hangs from a pole as shown in the figure . The uniform aluminum pole AB is 7.50 m long and has a mass of 12.0 kg. The mass of the traffic light is 21.5 kg. Homework Equations clockwise torques = counterclockwise torques The Attempt at a Solution...

Homework Statement A centimeter ruler, balanced at its center point, has two coins placed on it, as shown in the figure. One coin, of mass 10 g , is placed at the zero mark; the other, of unknown mass , is placed at the 4.7 cm mark. The center of the ruler is at the 3.0 cm mark. The ruler...

Consider the system on the attached picture showing a rectangular plate attached to a pole by two screws - one in A and one in B. Now to figure out the condition for equilibrium one would calculate the torques around point A and B to find that one screw must be pulling and the other one pushing...

Hi. I am working on this problem, which I have uploaded as a picture. I have a question to the sum of torques. Is there somebody how can explain me where all the sines and cosines comes from. I am not so good to the find sum of torques.

If anyone can give me some quick help on this, I would appreciate it. Thanks in advance.

When one finds the torque on a rectangular current loop one finds that it's equal to \vec m \times \vec B where m is the magnetic moment of the loop. I want to generalize this to arbirary current loops with constant current and I found that the torque would be equal to \left(I\oint...

Hi all... my first time here... I hope someone can help. I'm toying with a home project (in the early conceptual stage), and the attached picture shows "in general terms" what I'm trying to figure out. The outer 'wheel' rotates about its central axis, driven at that axis by a small motor...

hi I have multiple torques acting at different points on a rigid body I want to find the resultant force and torque (about the body CM) I think I can see how to "convert" an off-center torque to a torque + translation using the parallel axis theorem - but am wondering if there is a...

Hello, I have been watching a lot of Aircrash Investigations (also called Mayday) and it has gotten me interested in aerodynamics. I'm curious about what force would be needed to tip a plane over? Say that there was a sudden upwards gush of wind on the end of one wing (I am familiar with...

Homework Statement Why, for any system that is in rotational equilibrium, the torque about 1) any point on the object or 2) any point in space, must be zero.Homework Equations N/AThe Attempt at a Solution What I do not understand is, why the torque about ANY point on the object is zero...

Homework Statement Given a beam of 5 meters and uniform weight 100N position on a fulcrum such that it subtends an angle of 20 degrees and the length of the beam to the left of the fulcrum is 3.3m, how far could an 80N cat walk before the beam tips? Here is an image that I drew up in mspaint...

Homework Statement http://img51.imageshack.us/img51/5193/48593149.jpg Solutions [PLAIN]http://img444.imageshack.us/img444/9900/78057474.jpg [PLAIN][PLAIN]http://img84.imageshack.us/img84/8471/74918866.jpg The Attempt at a Solution I don't understand the solutions at...

Homework Statement The mass of the tray itself is 0.209 kg, and its center of gravity is located at its geometrical center. On the tray is a 1.11-kg plate of food and a 0.278-kg cup of coffee. Assume L1 = 0.0600 m, L2 = 0.108 m, L3 = 0.260 m, L4 = 0.366 m and L5 = 0.396 m. Obtain the force T...

Homework Statement Homework Equations Torque = r*F The Attempt at a Solution I've tried multiple times now to get the sum of the torques at the given points equal to zero but I can't figure out a way to do it. It just doesn't come close to becoming zero. Edit: Forgot to add...

Hi, here's the question: A massless, rigid rod has motors attached on each end. The motors are each connected to a massive disc, and the motors accelerate the discs in the directions indicated by the arrows. Due to the torque from the each motor on its disc and hence that on the rod and...

Homework Statement if the torque on a pivot point is zero does that mean the force acting on it is zero aswell? Homework Equations F = mg and T = F x D The Attempt at a Solution The sum of the torques in this lab that I'm doing isn't equaling zero... is this normal due to error...

torques and angular rotation... [b]1. Homework Statement [/b a grindstone used to sharpen tools is rotating at an angular speed of 8 rad/s when an axe is pressed against it. because of the torque produced on the grindstone by the force of friction between it and the axe, it comes to rest in...

So I was thinking physical a while back and I came up with some conceptual conundrums and I was hoping some fine folk can help me sort it out. So to change a particle's position, we must apply momentum. For this to be done we must apply a force. and for this, a yank and so on. My question...

Why do things rotate? I know what torques are...the question is deeper than that... This is not any homework or coursework problem. This question has been troubling me since it first popped into my head. Suppose there are two point masses both of mass m, connected to each other by a massless...

Homework Statement Write the necessary equation of the object shown in Figure P8.4. Take the origin of the torque equation about an axis perpendicular to the page through the point O. (Let counterclockwise torque be positive and let forces to the right and up be positive. Use q for θ and Rx...

QUESTION 1 WORK TO SOLVE QUESTION 1/SECTION1 - CONFIDENCE 80%

can you please explain why this (TLsin30.0° − w((L/ 2)cos30.0°) − w(Lcos30.0°) = 0) becomes this T sin30.0° − (3w/ 2)cos30.0° = 0 i though i can do all the transpose and other stuff. but i can't figure that one. i want to get the T. please help me.

Torque in Physics Simulation Let's say there is flat floor at y=0 . There is a rectangle of which two vertices are at (0,0) and (w,h). There is a ball in mid-air. Someone let's it fall and the ball falls until it hits the (w,h) vertex of the rectangle. The push-back force is very small and can...

Homework Statement A step ladder is moddelled as two model rods OA and Ab smoothly hinged at A. The other ends of the rods rest on a rough horizontal floor. The mass of rod AB is 4m and that of rod OA is m. The andle each rod makes with the vertical is theta. The origin is taken at O and the...

Homework Statement The mass m1 is 0.55 kg and it is located at x1 = 30 cm. The pivot point is represented by the solid triangle located at x = 45 cm. The mass of the meter stick (mms = 0.40 kg) is located at its geometric center, xms = 50 cm. The mass m2 is 0.35 kg and it is located at x2 = 80...

Homework Statement Find all cw and ccw torques. I don't know how to post the picture, but I was absent from my physics class today for AMC so I missed out. First problem: A horizontal massless rod of length 6 meters is pivoted about its center. There is a 2kg point mass on each end of the rod...

1. Homework Statement The steel shaft of a socket wrench is 18mm diameter and 450mm long. If the allowable shear stree is 70 MN/m^2. 2. Homework Equations i) What is the maximum permissible torque T that may be extered with the wrench? ii) Through what angle (theta) in radians will the...

Homework Statement A door with symmetry and of m 43.1 kg is 4.76 m high and 2.68 wide. The hinges are placed all the way on top and all the way on the bottom of the door. Find the absolute value of the horizontal force supplied by the bottom hinge.Homework Equations Sum of torques = 0 Torque =...

Torques: Rotational Equilibrium Mobile :) Homework Statement Please! I really need help figuring out how to make a balanced mobile! I would really appreciate anyones help! Directions: Apply what you know about torques by making a mobile. Shown below are five horizontal arms with fixed 1-...

Homework Statement and why is it FLcos(30)? Homework Equations The Attempt at a Solution So by looking at the soln, D(distance)=Lcos(30), which should be the hieght of the traingle. But the distances between a the forces at any point don't always add up to the hieght.. I am confused

This is not really a homework problem per se, it's just a question I thought of when attempting a circular motion problem. Imagine a motorcycle rider negotiating a bend on a level road. The centripetal force is then provided by lateral friction between the motorcycle's wheels and the road. At...

An object is at equilibrium at a certain time t if the sum of the forces and torques = 0. Look at the object from a moving frame, and apply the equations of special relativity. We find that Lorentz contraction means that in the moving frame (x',t'), there is no time t' such that the object is at...

Homework Statement A uniform rod of mass M sticks out from a vertical wall and points toward teh floor. If the smaller angle it makes with the wall is theta, and its far end is attached to teh ceiling by a string parallel to the wall, find the tension in the supporting string. Homework...

Homework Statement A horizontal uniform bar of mass m and length L is hung horizontally on two vertical strings. String 1 is attached to the end of the bar and string 2 is attached a distance L/4 from the other end. A monkey of mass m/2 walks from one end of the bar to the other. Find the...

Homework Statement Mountaineers often use a rope to lower themselves down the face of a cliff (this is called rappelling). They do this with their body nearly horizontal and their feet pushing against the cliff . Suppose that an 77.2- kg climber, who is 1.99 m tall and has a center of gravity...

Homework Statement Two cables are used to support a 24kg mass on 1.6 m long 8.0 kg unifrom horizontal beam. One cable is on each end of the beam and the mass is 0.6m from the right cable. What is the tension in the right cable? Homework Equations t=Fd Fg= mg The Attempt at a...

Hi guys. I haven't had physics in a couple of years and I'm trying to study for the MCATs. I've always had trouble with levers so I would really appreciate it if I could get some help. In particular, the following scenario confuses me: Say you have a man standing on a board, the fulcrum is to...

i have two questions from kleppner's book, here it goes (iv'e attached a file which have the sketchs of the two problems): 6.17 A rod of length l and mass m, pivoted at one end, is held by a spring at its midpoint and a spring at its far end, both pulling in opposite directions. The springs...

http://img208.imageshack.us/img208/392/untitledsx2.png this one seems so simple...i know the answer is 3 and 4; however, I do not know how my book came to that conclusion. can anyone explain to me exactly what is going on in the above diagram? Thanks

A traffic light hangs from a structure shown at http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=128765607&imageID=1460004546 The uniform aluminum pole has a mass of 8 kg and is 7.5m long. The traffice light has a mass of 5kg. The cables are massless. Cable 1 is...

It'd be best if I start with example. Screwdriver helps us by having a handle with a large radius that provides a mechanical advantage in turning a blade with a smaller radius. So whatever force exerted on screwdriver's handle by hand, same force is exerted on screw. But torque on a handle is...

Problem picture below: http://portfolio.iu.edu/whoblitz/problem2.PNG I know Newton's second law for torque torquenet=I*alpha and regular old Fnet=m*a, but I don't see how they fit together here (how I can account for frictional forces and torque at the same time). Help appreciated...

Is there any law of physics which forbids a mechanism by which several windmills located at different positions could be used to extract energy from the air current and to convert it into torque around one only axis ? Thanks Best Regards, DaTario

A square coil and a rectangular coil are each made from the same length of wire. Each contains a single turn. The long sides of the rectangle are twice as long as the short sides. Find the ratio tsquare/trectangle of the maximum torques that these coils experience in the same magnetic field when...

Ok. assuming that Torque is basically force at an angle (yes that is a very very loose description, I know). would it be fair to assume that net torque would be equal to all torques applied to one rotating shaft? Or are there exceptions to this?

I can't understand why I can't get this problem right. It's irritating me, so any help would be greatly appreciated. The Problem: The drawing shows a jet engine suspended beneath the wing of an airplane. The weight W of the engine is 9300 N and acts as shown in the drawing. The rotational...