Q. A 1 kg block rests against one end of a horizontal spring which is compressed by 10 $cm$. When the spring is released, the spring forces the block to slide across a table top. It stops 41 $cm$ from where you released it. The spring constant k is equal to 380 $N/m$. Calculate the constant of kinetic friction $mu_k$ between the block and the table.
Q. A rifle is aimed horizontally at a target 49 m away. The bullet hits the target 2.5 cm below the aim point. What was the bullet's flight time? and What was the bullet's speed as it left the barrel?