Скачать с ютуб Intro to Tension Forces - Nerdstudy Physics в хорошем качестве

Intro to Tension Forces - Nerdstudy Physics

Let's learn about Tension! What is tension? And when we think about tension in terms of tension forces and normal forces how do the two compare to each other? Nerdstudy's aim is to actually help you to learn (not in a haphazard way where you leave lessons feeling entertained but also still quite confused). We want you to be able to study the material deeply and master the content into your long-term memory! So without further ado, let's talk about Tension! Don't forget to Like and Subscribe!    / nerdstudy   Also, if you want to really buckle down and study like a true nerd, we've got all our lessons at: www.nerdstudy.com -- Suppose we’ve got a ball hanging from the ceiling by a rope. What is keeping the ball from falling to the floor anyways? After all, gravity is acting on the ball right? Well, it’s the rope that’s keeping the ball up! So the rope must be applying a FORCE on the ball to prevent it from falling. We call that force the TENSION force, because the rope is being put under tension by the ball. So any force that appears as a result of pulling on a rope, a string, or anything similar to that is called TENSION. Actually, we can think of tension forces as being, in a limited sense, the OPPOSITE of NORMAL forces. Now if you don’t remember what a normal force is, we encourage you to watch our videos on normal forces. Very briefly, we can say that a normal force occurs when a surface, like a table, resists being compressed by a force. The surface applies a force which prevents an object from moving INTO the surface, and we call that the NORMAL force. TENSION forces do something quite similar, except that instead of resisting COMPRESSION, they resist forces that cause things to STRETCH. For example, when we hang a ball on a rope, the rope applies a force to the ball which makes it resist being stretched out. The result is TENSION. Looking back at normal forces, it seems obvious that when an object is not pushing against a surface, the normal force must be zero. TENSION forces are similar to this, but in an opposite sense. If an object is not PULLING on a rope, the tension force is zero. Alright, I think we’ve got enough knowledge to look at a very simple example. Let’s look at the ball on a rope again. If the ball has a mass of 10 kilograms, what is the tension force? Hmm, how would we solve a question like that? Well, the answer would be 98.1 newtons upward. How did we get that answer? First of all, we have to look at the forces that are acting on the ball. One of them is obviously gravity. What other forces are there? Well, there’s really only one other force: the force of tension! More specifically, it’s the tension force being applied by the rope onto the ball. And since the ball isn’t moving, the forces must cancel out. So our next step will be to find the force of gravity on the ball. Cool! To find the force of gravity, in other words the weight, we’ll need to use Newton’s Second Law. We already know the mass of the ball, which is 10 kilograms. As for the acceleration, that’s constant near the Earth’s surface which is 9.81 meters per second squared downward. And once we substitute those values into the equation, we’d get 98.1 newtons downward for the weight of the ball. And since the gravitational force must be cancelled by the tension of the rope, we find that the tension force being applied by the rope on the ball is 98.1 newtons UPWARD.