Front assembly:  Put one washer on the bolt.  Push the bolt through the front hole of the body.  Put on another washer, then a wheel, then washer, and finally locknut.  Tighten the locknut such that the wheel is supported in an upright position but can still spin freely.

Mousetrap attachment:  Place the mousetrap on the center of the body.  Strap one rubber band on each end of the mousetrap.  Loop these rubber bands around the mousetrap such that the trap is held tightly.

Rear assembly:  Slide the rear axle through the rear axle hole until the center hole is in between the two supports.  Push one cotter pin through the hole in the center of the axle.  Slide four washers onto either side of the axle followed by a wheel.  Push one cotter pin in each wheel such that the loop of the cotter pin faces outward.  Push one more cotter pin through the loop of the one you just placed and through the outer hole in the axle.

Arm attachment: Cut the duct tape along the 3” side to create two 1.5” by 2” pieces.  Position the arm along the mousetrap arm such that they are parallel and the arm is on the outside.  Tightly wrap one piece of duct tape around both arms.  Wrap the second piece of duct tape around the first piece.

This mousetrap car is designed for torque analysis.  The lever arm coming from the mousetrap is adjustable in length.  Simply tie the string in a loop and feed it through one of the holes in the arm.  Loop it around itself to secure.  To wind the string, loop the string around the center cotter pin in the rear axle and turn in the reverse direction.  The rear axle is designed to accommodate quick wheel changes to test wheels with different diameters or shapes.  Remove the axle cotter pin and slide the wheel off for a quick change.  Both of these variables can be adjusted simultaneously for more in-depth testing.