transamz9 wrote:
Hannibal wrote:
transamz9 wrote:
You really don't understand that a lever creates torque. When you open a door, you are creating torque. When you drive across a bridge with your truck you are creating torque on the bridge. Yes when you drop the hitch of a travel trailer on the hitch the rear wheel becomes the rotational center point.
Here's a little write up with pictures.
Torque and Rotation
You go ahead and stick with the door hinge theory. Door hinges are idle. They neither produce nor use torque. A door closer however uses torque produced by a coil spring to turn a shaft to which a hinged arm is attached to pull the door closed.
When you drop the coupler of a trailer onto the hitch ball, the rear axle of the truck becomes the axis between the ball and front wheels. You seem to be suggesting that the tongue weight produces a rotational force on the rear wheels. Would that be forward or reverse rotational force? Which way will the rig move due to weight on the hitch ball?
It take force to rotate the door on the hinge. That force is torque applied. Think of it as one of those rotating glass doors that you go through that rotates on an axle. You have to apply torque to get it rotating. Once it is rotating then you are making HP because if you continue to keeping going around that axle that the door is spinning on you are creating RPM. It takes a curtain amount of torque applied to the door to keep it rotating. If you quit applying the torque the door will stop.
The door on the hinge is no different. You just can't keep going around in circles around the hinge.
The tt hitch is applying torque down on the hitch trying to push it by rotating on the rear tires. If you didn't have the torque the front of the truck is applying in the opposite direction then the truck would stand straight on it's rear until something strong enough overcame the torque force which in this case would be the ground.
Look at it this way:
Looking at the truck from the drivers side, the axle and wheel is the stud. The rear end housing is the lug nut. The truck is a 4-way lug wrench that is attached to the lug nut. When putting the tt hitch on the ball is like you pushing down on the lug wrench with your right hand tightening the lug nut.
With the front of the truck weighing what it does, the torque it is applying resisting the torque applied by the tt is greater so the front stays on the ground (although lighter)
No. A lug wrench is creating torque on the wheel. You can move the vehicle with a lug wrench. Putting weight on the ball doesn't put rotational force on the wheel. The wheel is simply an idle axis as the weight is leveraged over it. No different than putting weight over the axle. It will not move the vehicle forward or reverse nor will it even try to.
When you go through a revolving door, you are pushing on the door panel. You are not twisting it's axle to move it. If you put a wrench on the end of the axle and exerted a rotational force on it to rotate the door panels, then you would be using torque to rotate the doors. There will be available torque at the axle that could be used to perform some function but, as it is, the axle is just an idle axle no different than the idler pulley on your serpentine belt. It is not causing the rotation of the doors nor is it's rotation being used to perform work at the other end.
