Ok, now consider the following. Consider opening a door. Which of the two locations would you push on to best open the door? Please tell me that you would push at location B to open the door.
Why would you do that? Also, why is the door handle on the side farthest from the hinge? Why is it not in the middle?
Obviously, that would be a bad idea well, it is a bad idea unless you are a Hobbit. To open the door, you need it to rotate. The torque would be: F and r are really vectors. In the above formula for torque, F and r are the magnitude of the vectors.
Technically, torque is also a vector - but that might be a little too much at this point. Just pretend like it is a scalar and everything will work out fine. Oh, torque can be positive or negative. If you diagram is 2D, you can still choose where the positive direction is along the remaining 3D orthogonal direction In defining angular quantities like torque or angular momentum, you have also the choice of placing the origin of coordinates where you want, but typically expressions become much simpler when the origin of coordinates coincides with a point of symmetry in the problem.
Improve this answer. Thales Thales 2 2 bronze badges. Doing so is contrary to the spirit and "rules" of the forum. I suggest you edit the answer to address only the issue of the torques. John Alexiou John Alexiou Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown.
Featured on Meta. Now live: A fully responsive profile. Related 3. If it were on a frictionless surface and not fixed in place,. A large ocean-going ship runs aground near the coastline, similar to the fate of the Costa Concordia , and lies at an angle as shown below. Salvage crews must apply a torque to right the ship in order to float the vessel for transport. A force of. What is the torque about the point of contact of the ship with the ground Figure?
The sign of the torque is found using the right hand rule. If the page is the plane containing. The net torque can be found from summing the individual torques about a given axis. Conceptual Questions What three factors affect the torque created by a force relative to a specific pivot point?
Give an example in which a small force exerts a large torque. Give another example in which a large force exerts a small torque. When reducing the mass of a racing bike, the greatest benefit is realized from reducing the mass of the tires and wheel rims. The moment of inertia of the wheels is reduced, so a smaller torque is needed to accelerate them.
Can a set of forces have a net torque that is zero and a net force that is not zero? Can a set of forces have a net force that is zero and a net torque that is not zero? Two flywheels of negligible mass and different radii are bonded together and rotate about a common axis see below. The smaller flywheel of radius 30 cm has a cord that has a pulling force of 50 N on it. What pulling force needs to be applied to the cord connecting the larger flywheel of radius 50 cm such that the combination does not rotate?
The cylindrical head bolts on a car are to be tightened with a torque of If a mechanic uses a wrench of length 20 cm, what perpendicular force must he exert on the end of the wrench to tighten a bolt correctly? What torque are you exerting relative to the hinges?
There is only one pair of hinges. When tightening a bolt, you push perpendicularly on a wrench with a force of N at a distance of 0. How much torque are you exerting in newton-meters relative to the center of the bolt?
What hanging mass must be placed on the cord to keep the pulley from rotating see the following figure? The mass on the frictionless plane is 5. The inner radius of the pulley is 20 cm and the outer radius is 30 cm. A simple pendulum consists of a massless tether 50 cm in length connected to a pivot and a small mass of 1.
What is the torque about the pivot when the pendulum makes an angle of. Calculate the torque about the z -axis that is out of the page at the origin in the following figure, given that.
A seesaw has length The pivot is located at 6. What magnitude of force needs to be applied perpendicular to the seesaw at the raised end so as to allow the seesaw to barely start to rotate? A pendulum consists of a rod of mass 1 kg and length 1 m connected to a pivot with a solid sphere attached at the other end with mass 0. What is the tension necessary to produce this torque? Would it be easier to raise the drawbridge if the angle. A horizontal beam of length 3 m and mass 2.
What is the torque of the system about the support at the wall? What force must be applied to end of a rod along the x -axis of length 2. Skip to content 10 Fixed-Axis Rotation. Learning Objectives By the end of this section, you will be able to: Describe how the magnitude of a torque depends on the magnitude of the lever arm and the angle the force vector makes with the lever arm Determine the sign positive or negative of a torque using the right-hand rule Calculate individual torques about a common axis and sum them to find the net torque.
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