Two blocks in contact with each other are pushed across a rough horizontal surface by an 83 N force. The force is applied on the 6.7 kg block and transmitted to the 8.6 kg block. The coefficient of kinetic friction between each of the blocks and the surface is 0.076.
When the force of 83 N is applied on the 6.7 kg block there is a counteracting force due to the force of friction between the block and the surface. This is equal to 6.7*9.8*0.076 = 4.99 N
The net force that can be exerted by the block with a mass of 6.7 kg on the other block with a mass of 8.6 kg is 8.3 - 4.99 = 3.3 N
When a force of 83 N is applied on the block weighing 6.7 kg the force exerted by it on the 8.6 kg block is 3.3 N.