A crate slides along a horizontal frictionless surface at a constant speed of4.0 m s − 1. The crate then slides down a frictionless incline and across a second frictionless horizontal surface. What is the crate's speed at the bottom of the ramp?

Average speed is total distance over total time. Total distance, 10-3 blocks, seven blocks. 12 blocks is the same as 1 kilometer, this information can be used to create a conversion factor. We want to change blocks to kilometers: 7 blocks × 1 kilometer÷12 blocks=7/12 kilometers. Now we can find time in hours. 10:49:30-10:32:00=17:30 or 17.5 minutes. Change this to hours: 17.5minutes×1 hour/60 minutes=17.5/60. Remember, total distance divided by total time: 7/12 ×60/17.5= 2kilometers per hour. (I always hate when the answer is like that.)