Sam helped move boxes in the classroom. He pushed a heavy box, but it barely moved. Then his friend Pat helped him push the same box from the same side. Together, their push was stronger and the box moved easily! When they pushed from opposite sides, the box didn't move at all.
Why did the box move better when Sam and Pat pushed together?
The box became lighterTheir push was strongerThe box had wheelsThey were tiredWhat happened when they pushed from opposite sides?
The box moved fastThe box moved slowlyThe box stayed stillThe box fell over