determination of force needed to keep objects moving at constant speed?

Question

I have a figure with two boxes attached to a pully, sitting on each other. M1 needs to go to the left or towards the pully and M2 needs to go away from the pully. The pully is situated to the left of both blocks.

How can I determine the force (F) needed to keep two blocks moving at a constant speed-m2 to the rigth and m1 to the left. assume both the frictionless pulley and the rope to be massless: m1 has a weight of 5.0 N and m2 has a weight of 10 N; and µ k=0.40 for all surfaces.

Answer 1

It is difficult to visualise in the absence of a figure.
I assume only frictional forces have to be overcome.
Because of the motion of pullies as described, the frictional forces are adding up.
Hence total force required to keep the blocks in motion
=force reqd to overcome frictional frces
=Mu*5+mu*10 Newtons
=15*mu
=15*.4
=6 Newtons

Answer 2

Well if m1 is on top of m2,the force is applied on m2.
Let the tension in the string be T
Hence for m1 to move at constant speed,
T = frictional force on m1 = 5*0.4 = 2N
Now the forces acting on m2 are T (left),Friction(left)
and the applied force F (right).
Hence F = T + (5+10)*0.4 + 5*0.4 = 2 + 8 N
or F=10 N.
Reason for the (5+10)*0.4 term is that the normal force from the ground on m2 is the sum of weights of m1 and m2 since m1 is on m2.

Best Answer?

Answer 3

I'm not quite 'seeing' the setup you describe, but the only real thing that you have to remember is that the sum of the forces has to add up to zero if they boxes are moving at constant speed. So just calculate all of the frictional forces involved, add them up, and there's the total force required to hold a constant speed.


Doug

Answer 4

particular and known relativity are very complicated concepts, they go hostile to "straightforward experience" a million) issues do no longer have absolute values , they have measured values if the observer is transferring on the same speed of the objective the observer measures "relax values" If the observer is transferring with v, a speed with appreciate to the objective, the observer measures "switched over values", on the problem of v^2/ C^2 in a time period called gamma the guidelines bending theory is that truth is merely what's measured and a transferring observer can in no way boost up the objective because in Einstein alterations the mass, speed and length contained in the course of speed determination with v. surprisingly the Y and Z length do no longer replace i do no longer understand the maths both. that's from interpreting about relativity magnetism is the rigidity of static electrical energy as considered by transferring rates. if the rates are transferring with the same v merely static rigidity is degree ( it truly is what my professor reported , i ought to no longer stick with the maths) all this math is to save the fee of C the same for all accessible observers. It changed into experimentally talked about by Michaelson and Morley contained in the late 1800s yet they could no longer understand why they could no longer degree a replace in C . Einstein reported, assume C is consistent, what may the universe be like E + mC^2 turned right into a end derived from the maths and, lo and behold, the A-bomb did explode it defined why the sunlight shines, it can not likely be burning like fireplace Newtons concepts of absolute area and time and merchandise having one and easily one fee are the "straightforward experience" concepts because any v on earth is so below C that gamma is "quite a lot a million" and measured values in no way replace yet with atomic experiments it truly is critical. even the former television tubes with electron beams had to take it under consideration the GPS area device relies upon on Relativity because the satellites and their clock are transferring for some unknown reason : gentle merely exists even as in action at speed C. what we "see" is gentle AFTER it has hit the atoms contained in the cells of our eyes