Experiencing same acceleration?

[aeromat]

Homework Statement

5kg block is placed on top of a 10kg block. A horizontal force of 45N is applied to the 10kg block, while the 5kg block is tied to the wall. The co-eff of kinetic friction between the moving surfaces is 0.2

(b) Determine the tension in string and acceleration of the 10kg block.

Homework Equations

Newton's Laws

The Attempt at a Solution

Direction of acceleration: --------------------------->

5kg Force summations
I said tension is the opposing force towards the direction of acceleration, thus it is negative and friction is positive. The block will go in the opposite direction of motion whe the bottom block is applied forward, thus frictional force is pointing right.

The Ff force for both blocks is the same

Summation of Fx = [Ff - Ft = -m1*a]
Summation of Fy = [Fn - m1*g = 0]

10kg Force summations
Summation of Fx = [Fa + Ff = m2*a]
Summation of Fy = [Fn - m2*g = 0]

Using known values

Fa = 45N
Coeff of Kinetic friction = 0.2
Mass of top block = 5kg
Mass of bottom block = 10kg

Subbed in Summation of Fx for 10kg to solve for a
45 + (0.2)(5)(9.81) = (10)(a)
5.481 m/s^2 = a

Now, I am stuck; I don't know how to get the tension force. How do I do so? Are they experiencing the same acceleration?

 

[master117]

Since it is tied to the wall it really doesn't move so the sum of Fx for block 5kg is tension equals to the friction force

 

[SammyS]

Draw a free-body diagram for each block.