Force and Motion

• Mac was a lonely soccer ball. Mac sat for hours and often pondered about the forces keeping him at rest on the green soft grass of his soccer field.

• Mac decided there were at least three forces acting upon him to keep him still.

• Can you name them?

• Correct! Air pressure, gravity, and the ground are all forces that keep him at rest.

• The forces are balanced since the net force results in zero movement.

• One day, a kid walks up to Mac and kicks him 15 yards eastward!

• The force of the kick is an unbalanced force and causes Mac to move.

• In flight, other unbalanced forces act upon Mac, that make him fall back to the ground and eventually comes to rest again.

• Name at least two of these unbalanced forces.

• Correct! Friction (Air Resistance) and gravity act upon Mac, slowing him down, until he comes to rest.

• Once at rest, the original three balanced forces (what are they?) act upon Mac again to keep him at rest.

• Now the same kid comes up and kicks Mac once again, sending him into the air. However, this time a nearby cliff causing him to fall at at increasing speed.

• When mac hits the ground, another unbalanced force(the ground) acts upon him, slowing him down.

• Additional forces now act on Mac slowing him down even more.

• What are two of these forces?

• Correct! Once again gravity and air resistance (friction) are unbalanced forces resulting in a change of speed.

• Eventually, these unbalanced forces cause Mac to slow down come to a rest.

• Once at rest, the original balanced forces(what are they?) act upon Mac to hold him still again.

• Until another unbalanced force causes him to move from his station in life.

• Morale:

• Sometimes boredom is better than an unbalanced force.