Pulley problem, find total mass where ther is no acceleration

[vande060]

Homework Statement

you need to see the picture for this one

http://s861.photobucket.com/albums/ab174/alkaline262/?action=view&current=prob13.jpg

Homework Equations

f=ma

The Attempt at a Solution

i don't really know where to start on this one.

i have the equations for force

2T - m2g = -m2a2

N - m1g = 0

T = m1a1

i think i should set a to zero

2T = m2g
T=0

that step doesn't make sense to me, because how can the tension = 0 ?

 

[Liquidxlax]

are the pulleys negligible?

 

[vande060]

are the pulleys negligible?

yes they are

 

[vande060]

bump. i still don't understand this problem when i solve for t is get t = -2g/(1/m1 - 4/m2)

is that right? what can i do with it ?

 

[rwisz]

To solve this pulley problem, we can use Newton's Second Law, which states that the net force on an object is equal to its mass multiplied by its acceleration (F=ma). In this case, we have two masses (m1 and m2) connected by a pulley. The pulley is assumed to be massless and frictionless, so we do not need to consider its effect on the system.

To find the total mass where there is no acceleration, we need to set the net force on the system equal to zero. This means that the forces acting on the system must be balanced. Looking at the forces in the x-direction, we have the tension force (T) pulling on the pulley to the right and the weight of m1 pulling it to the left. Since the system is not accelerating, the tension force must be equal to the weight of m1 (T=m1g).

Next, we can look at the forces in the y-direction. Here, we have the normal force (N) pushing up on m1 and the weight of m2 pulling it down. Since the system is not accelerating in the y-direction, the normal force must be equal to the weight of m2 (N=m2g).

Now, we can substitute these values into our equations to solve for the total mass. We have T=m1g and N=m2g, so we can rewrite the first equation as 2m1g=m2g. Solving for m2, we get m2=2m1. This means that the total mass of the system is equal to three times the mass of m1 (m1+m1+m2=3m1).

In summary, to find the total mass where there is no acceleration in this pulley problem, we need to set the net force on the system equal to zero and solve for the total mass. This involves using Newton's Second Law and balancing the forces in the x- and y-directions.