# Homework Help: Tension/ Force problem; How should I look at this?

1. Sep 29, 2008

### kleencut

1. Three identical blocks connected by ideal strings are being pulled along a horizontal frictionless surface by a horizontal force F. The magnitude of the tension in the string between blocks B and C is T= 3.00N. Assume that each block has mass m= 0.400kg .

[a]--------[c]---->F

What is the magnitude F of the force?

What is the tension between block a and b?

2. F=ma;

3. The magnitude of the force should equal m*a, so (.4*3)*(3/.8) should provide the magnitude. And from that (.4)*(3/.8) should give me the answer to the second question. I feel that I am making some unwarranted assumptions. Please help

2. Sep 29, 2008

### dirk_mec1

T=2*m*a => 3.00=2m*a => a is known

F=3*m*a =>....

3. Sep 29, 2008

### kleencut

Ok so a= 3.75 m/s^2; From this: F= 1.2*3.75; F=4.5N; T=.8*3.75; T=3N ?

4. Sep 29, 2008

### kleencut

No, btween a and b m=.4; so T= 1.5N

Thanks, I understand now!! :-)

5. Sep 29, 2008

### dirk_mec1

OK! Good luck!