Balance and unbalanced forces for studentsPresentation Transcript
MotionEvent that involves a change in theposition or location of something.
What is a Force?• Definition: A force is a push or pull that causes an objectto move, stop, or change direction• In physics, a force is anything that makes an objectaccelerate
Balanced and Unbalanced ForcesForces occur in pairs and they can beeitherbalanced or unbalanced.
Balanced and Unbalanced ForcesPicture A: The forces are __________.Picture B: The forces are _____________.PICTURE A PICTURE Bbalancedunbalanced
Examples of Balanced Forces
Balanced Forces• Balanced forces are equal forces acting on anobject in opposite directions (the object is still)• Balanced forces do not cause change in motion• They are equal in size and opposite in direction
Unbalanced ForcesUnbalanced forces are unequal forces acting onan object which cause it to move
Unbalanced Forces• An unbalanced force always causes a change in motion• Also, when unbalanced forces act in oppositedirections you can find the net force
Net ForceNet force is the overall force acting on an object.It is a combination of the magnitude (differencebetween 2 forces) and the direction (direction ofthe largest force).4 N, Left -10 N, right = 6 N, right=
Examples of Unbalanced ForcesGravity is a constant force. Theparachute is working againstthe force of gravity.The person’s finger is pushes thetoy truck. The truck moves in thedirection of the greatest forceoccurring on it. Some force isacting against the finger, but thatisn’t strong enough to resist.
More Examples of Unbalanced ForcesThe soccer ball doesn’t moveuntil the girl provides anunbalanced force upon it.The tug of war doesn’t have thesame amount of people oneach side - the forces areunequal. One side will movemore than the other.
Gravity as a ForceLet’s look at a demonstration of gravity at work:What’s this? rubber bandWhat are these?
Gravity as a Force Explanation: the rubber band stretches as the weightpulls on it. The weight is being pulled down by the forceof gravity. The spring scale measures in NEWTONS theamount of force acting on the rubber band.Newtons (N) – themetric unit used tomeasure force
Gravity as a Force• The rubber band in turn exerts an upward force on the weight.What happens when more weight is added?• The additional weight adds or INCREASES the amountof force acting on the rubber band. As this forceincreases, the length of the rubber band increases.• Weight is a downward force caused by the force ofgravity pulling objects to the center of the Earth.
Spring Scale• Definition: a spring scaleis a tool used tomeasure force.• It works in the same waythe rubber band does.• The spring insidestretches based on theamount of force beingexerted.
“Reading” Pictures of UnbalancedForces3 N, right – 6 N, left = 3N, leftNumber means magnitude,and the direction of the force is left1. In pictures aboutforce, there will be agraphicdemonstrating theforce.2. Then there arearrows showing thedirection andmagnitude orstrength, of theforces.3. The formula showseven more detail.
Force – A push or pull on an objectExamples: pushing a shopping cartor pulling a wagonBalanced Force – Equal forces acting on an object inopposite directions. (Object is still)Examples:Unbalanced Force – Unequal forces acting on anobject which causes it to moveExamples:Net Force – a combination of themagnitude (difference between 2 forces)and direction (direction of largest force)Example:Newton (N) – The metric unit of measuringforceExamples:Spring Scale – A device that measuresthe tension force acting on an objectExample:4 N, left – 10 N, right = 6N, right