Reaction force Definition and 112 Threads

I'm trying to write a Library entry on Reaction Force, and I've discovered I can't answer this very simple question. :redface: Two equal blocks are on a horizontal table, with a gap between them. A straight rod is placed above the gap, but not symmetrically, resting on both blocks, with an...

Homework Statement In my homework we are asked to find the magnitude of the reaction force at the pivot at a instant and earlier in the problem we found the magnitude of the angular speed at one instant, the magnitude of the angular acceleration at the same instant, and the magnitude of the...

for example, a book is at rest on a table. One might say that the normal force is the reaction force. BUt reaction forces always have to be equal in magnitude, and you put an object on the book, then the normal force would increase to keep the book at rest, therefore the normal force is...

Homework Statement http://tunerspec.ca/school/question3.gif The Attempt at a Solution This should be easy, but I'm tired and just can't do it. If anyone can point me in the right direction that'd be great. I tried making a FBD, and had the equations: Tsin30^{\circ} - 752N = 0 344N -...

It is often stated that ANY accelerating charge radiates, so this includes uniformly accelerating charges. But the radiation reaction force is proportional to the THIRD derivative of x, so it vanishes when acceleration is constant. What's the deal here? Here's a graph which supposedly shows...

Homework Statement A wedge of mass 4kg and angle 30 degrees is at rest on a smooth horizontal table. a mass of 1kg is placed on the smooth inclined face of the wedge and a horizontal force of 10N is applied to towards the vertical face of the wedge. Show that the acceleration of the wedge is...

Hi I've got a question concerning a previous question I've done. A person is holding a toy airplane which flys in the air with a constant radius. is the lift force the same as reaction force? is it equal to the vertical component of the centripetal force and weight force of the airplane?

The problem involves drawing a free-body diagram: A book lies on a flat table. It is given that the weight of the book is 20N. I assume that since the book is not moving, the Fn (normal force) should also be 20N. The next part of the problem states that a string tied to the middle of the book...

Question: A book is resting on top of a table. 1. Do the downward force of gravity and the upward force of normal force constitute a 3rd law pair? (Yes/No) 2. The reaction to the force of gravity is exerted on the (earth/table/book) by the (earth/table/book). Its direction is...

Is it true that there are cases in which the radiation reaction force on an electron is nonzero even if its acceleration is constant? I am confused because the radiation reaction force is proportional to the time derivative of the acceleration. Also when considering the radiation reaction...

Can anyone explain how a reaction force (for example the electrostatc force of the Earth on the stone, and the force of the stone on the earth) works on a molecular level? what is actually happening to *repel (if it does indeed repel??) the object

if an object is falling to earth, is the equal and opposite force to gravity (Newtons 3rd law) the pull of the Earth towards the object?