FORCES Chapter 12 1 What is a force

FORCES Chapter 12. 1

What is a force? FORCE = a push or a pull that acts on an object. A force can cause a resting object to move, or it can accelerate a moving object by changing the object’s speed or direction.

Units of Force is measure in NEWTONS (N) One Newton is the force needed to cause a 1 kg A Newton is mass to accelerate 1 meter per second each 2 1 kg∙m/s second. 1 N 1 kg a = 1 m/s 2

Newton Named after Sir Isaac Newton (1642 -1727) English scientist who explained how force, mass, and acceleration are related. http: //www. biography. com/people/isaac-newton-9422656

Representing Force is a VECTOR! It has magnitude AND direction. Direction Length ofof arrow = magnitude = direction of of force

Combining Forces in the same direction…ADD together Forces in opposite directions…SUBTRACT!

NET FORCE = the overall force acting on an object after all the forces are combined Net Force = 3 N 5 N 2 N

Balanced Forces When forces on an object are balanced, the net force is zero and there is no change in the object’s motion. 2 N 2 N

Tug of War Both sides pull on the rope with the same force in opposite directions…forces are balanced (net force of zero) and neither side wins.

Unbalanced Forces Unbalanced force = a force that results when the net force acting on an object is NOT zero. When an unbalanced force acts on an object, the object accelerates.

Review 1. ) Which is not a force? a. friction b. gravity c. momentum d. weight

Review 2. ) What is the net force on the box? 3 N