Force on an Object: Find Force Exerted by 7.0kg Block

[kdb004]

Homework Statement

Blocks with masses of 1.0 kg, 7.0 kg, and 9.0 kg are lined up in a row on a frictionless table. All three are pushed forward by a 20 N force applied to the 1.0 kg block.

A) How much force does the 7.0 kg block exert on the 9.0 kg block?

B) How much force does the 7.0 kg block exert on the 1.0 kg block?I am unsure of where to start or an equation to even use. help on how to solve it would be greatly appreciated

 

[The legend]

for most of the mechanics problems draw the FBD(labeling all forces) and put in equations obeying F=ma...and solve.

PS: try posting atleast your idea of the problem..