"ZERO" the force sensor. Click RECORD in Capstone and gently push the blue cart against the red cart so that the block and two carts move along the track at a constant velocity. Ensure that the block travels as parallel as possible to the grooves in the track. Once you reach the middle of the track, click STOP. (Step 3 of Instructions Part B)

Draw a free body diagram of the block and red cart (treated as a single mass) when they are being pushed at a constant velocity on a horizontal track (described in Part B - Step 3 of the instructions).