Testing Forces and Motion Practice Test

In class, Maya slides a book on a smooth table from the same spot. She asks, “Do different surfaces need different push strength to move?” She will use the same book and start line each time. What should Maya keep the same for a fair test?

Yuki rolls a ball from the same tape line on the gym floor. She tests, “Will a harder pull back make the ball roll farther?” She pulls back softly and then harder. What should Yuki keep the same for a fair test?