What is a Force? “May the force be with you.”

S8P3: Students will investigate the relationship between force, mass, and the motion of objects. a. Determine the relationship between velocity and acceleration. b. Demonstrate the effect of balanced and unbalanced forces on an object in terms of gravity, inertia, and friction.

What Is A Force? Forces Act On Objects Forces in Combination Unbalanced and Balanced Forces

Demonstrate the effect of balanced and unbalanced forces on an object in terms of gravity, inertia, and friction. 1.What is a force? 2.What is a net force? 3.Examples of forces in the same direction. (including illustration) 4.Examples of forces in the opposite direction (including illustration).

5. Define unbalanced force and know what it produces. Give at 2 examples of objects with unbalanced forces. Define balanced force and know what it produces. Give at 2 examples of objects with balanced forces.

We often use the word “force” in everyday conversation: “The storm had a lot of force.” “Our softball and football teams are forces to be reckoned with.” “A flat tire forced me to stop riding my bicycle.” “The inning ended with a force-out at second base.”

In science, a force is a push or pull. All forces have size and direction. Forces are everywhere. Anytime you see something moving, you can be sure that it was a force that its motion was created by a force. Scientists express force using a unit called the newton (N). The more newtons, the more force.

Forces Act on Objects All forces are exerted by one object on another object. For any push to occur, something has to receive the push. You can’t push nothing. The same is true of a pull.

Why doesn’t the force exerted on the chair by the man cause it to move? The earth is also exerting a force on the chair. The man is pushing down on the chair and the earth is pushing up on the chair.

It is not always easy to tell what is exerting a force or receiving a force. You cannot see the force that pulls magnets to refrigerator.

Forces in Combination Often more than one force is exerted on an object at the same time. The net force is the force that results from combining all the forces exerted on an object.

How is net force determined? Forces in the Same Direction When the forces are in the same direction, you add the forces together to determine the net force. One of the men is pushing on one end of the piano, and the other man is pulling on the other end.

Forces in Different Directions When the forces are in different directions, you subtract the smaller force from the larger to determine the net force. The larger dog is exerting the greater force.

Unbalanced and Balanced Forces Unbalanced forces produce a change in motion. When the net force on an object is not 0, the forces on the object are unbalanced. Unbalanced forces produce a change in motion (acceleration). Unbalanced forces are necessary to cause a nonmoving object to start moving.

Unbalanced forces are also necessary to change to motion of moving objects. The soccer ball received an unbalanced force and moves in a new direction with a new speed.

Balanced Forces Produce No Change In Motion When the forces applied to an object produce a net force of zero, the forces are balanced. Balanced forces do not cause a nonmoving object to start moving. Balanced forces will not cause a change in the motion of a moving object. acting on them. Many object around you have only balanced forces