The same unbalanced force will change the motion of an object with more mass more slowly than an object with less mass.
Force and Motion
In prior grades students learned to use basic tools to measure force, time, and distance. In grades 6-8 students learn to measure, record, and calculate the average speed of objects and to tabulate and graph the results. They also develop a qualitative understanding of inertia. Students learn to predict the motion of objects subject to opposing forces along the line of travel. If the forces are balanced, the object will continue moving with the same speed and direction, but if the forces are not balanced, the object’s motion will change. These concepts and principles prepare students for a more formal understanding of mechanics in high school and help them make sense of the world around them.