Unit 3

Unit 3Forces1. What is a force?A force can cause a resting object to move, or it can accelerate a moving object by changing the objects speed or direction.A force is a push or a pullUnits of force is Newtons (N)

Force is calculated using:

F= maF= forcem= mass (kg)a= accleration2. Free body diagrams (FBD)Show all the forces acting on a bodyForces are drawn from the center of mass

3. Combining ForcesCombine force arrows to show the result of how forces combine (known as the resultant)Forces in the same direction add togetherForces in opposite direction subtract from one anotherNet force is the overall forces acting on an object after all the forces are combinedExamples:Adding forces:

Push and pull on an object in the same directionSubtracting forces: when two forces oppose each otherComplete Forces Worksheet 14. Balanced ForcesWhen the forces on an objects are balanced, the net force is zero and there is no change in the objects motion.

5. Unbalanced forcesWhen an unbalanced force acts on an objectSpeed upSlow downChange directionStop moving

Wow, this one is not going to win a Nobel Prize6. List of forcesWeight (Fg): Force of gravity pulling down on an objectFg=mg

Normal force (FN): Opposite of weight (Fg)

10Applied Force (FA): any push or pull on the object

Frictional Force (Ff): force that opposes motion

Four types of FrictionStatic: friction force that acts on objects that are not moving, acts in the direction opposite to the applied forceSliding: opposes the direction of motion of an object as is slides over a surface

3. Rolling: A change in shape caused by rolling objects

4. Fluid: opposes the motion of an object through a fluid.

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