Direction and Force

FORCE

Force is a push or pull. When force is applied on an object at rest, the object may move. A force applied on a moving object will cause that object to stop, slow down, or change direction. Force can also cause to change shape or size. You may squeeze, cut into pieces, and form different shapes on a clay by applying force on it.

Effects of Force on Objects

Motion

Force can make things move. Motion is a change in an objects position. It is the result of forces acting on an object. Forces acting on objects may be balanced or unbalanced.

Unbalanced forces are forces acting on a body that may be in the same direction or in opposite direction but different magnitudes. Unbalanced forces make objects speed up, slow down, or change direction.

​Unbalanced Forces

Balanced forces acting on an object are of the same magnitude but in opposite direction. A book placed on top of a table is acted upon by balanced forces. Namely, the force of gravity pulling the object down and the force of the table pushing the book up. In this case, the force of gravity and that of the table are equal. The book stays at rest. No motion is observed. If an object is not moving, it is said to be at rest or in stationary position.

​Balanced Forces

Balanced and Unbalanced Forces

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Change in Shape and Size

When forces are applied on some objects, such as modeling clay or toothpaste tube, a change in size and shape is observed. These changes are seen on cut pieces of paper and crushed plastic cups. Squeezing a lemon fruit, smashing a tomato, or straightening a loop of wire illustrates how force can also change the shape and size of objects.


You can change the size and shape of objects by pushing, pulling, compressing, stretching, twisting, bending, pounding, squeezing or cutting.