Tension & pulling blocks?

Question

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

1.) What is the magnitude of the force?

2.) What is the tension T sub AB in the string between block A and block B?

How do you do these?

Answer 1

Using the formula:

F = ma

For the string between B and C:

a = F/m = 3/.4 m/sec^2

1). For the total horizontal force pulling the there mass of m

F = (3 x.4) x(3/.4) = 9 N

2). For the tension of the string between block A and block B;

T = (2 x .4) x (3/.4) = 6 N

Answer 2

We need the diagram that came with this problem to solve it properly.  However, I'll take a guess.

1) 9.00 N

2) 6.00 N