1. The problem statement, all variables and given/known data A small block of mass 1.74 kg rests on the left edge of a block of length 3.05 m and mass 7.95 kg. The coeﬃcient of kinetic friction between the two blocks is 0.279, and the surface on which the 7.95 kg block rests is frictionless. A constant horizontal force of magnitude 11.4 N is applied to the 1.74 kg block, setting it in motion. How long will it take before this block reaches the right side of the 7.95 kg block? The acceleration of gravity is 9.8 m/s2 . (Note that both blocks are set in motion when ~ F is applied. Answer in units of s. 2. Relevant equations Ffk=Uk(FN) X=(1/2)at^2 F=ma 3. The attempt at a solution so to find the normal force (FN) that mass 1.74 exerts on the block below it I did 1.74kg*9.8m/s^2 to get a normal force of 17.052N. I then found the kinetic friction by multiplying the normal force by the coefficient of kinetic friction: 17.052N*.279=4.757N. I then found the net force exerted on the top block to be 11.4N-4.757N= 6.64N. so using F=ma I used the numbers: 6.64N=1.74kg*(a) and solved for a to be a=3.8175m/s^2. Then I used X=(1/2)a(t^2): 3.05m=(1/2)(3.8175)(t^2) and got t=1.264s. However, this time is apparently not correct and I am confused as to what I am doing wrong. Do I need to take into account that the bottom block is moving aswell?