# AP Physics 2: 2.3 Object Interaction and Forces

AP Physics 2: 2.3 Object Interaction and Forces. What is the net force in this situation?

AP Physics 2 | Object Interaction and Forces |

Language | English Language |

Science Practice 2 | Using math appropriately |

### Transcript

tug of war over They didn't pay attention in physics

Instead of dispersing themselves equally they distributed themselves as in

the diagram scene right chair with one person on either

side And one person in between The person on the

left pulls with a force of nine Newton's The person

on the right pulls with a force of twelve noons

and the person this guy right here on top pulls

with a force of four news what's the net force

in this situation and here the potential answer sounds like

a movie star Cary grant Okay well this will be

quite the interesting tug a war match Let's Just hope

no one gets hurt Is there drag along the ground

but looking at the set up here we know we're

dealing with vectors And to find the total sum of

vector forces we can add them up Yeah once your

vector Victor All right Well let's think of this three

headed monster as if it was on a coordinate plane

A different kind of plain The middle point will be

zero for both axes The first time pulling toward the

left will be a point negative nine zero And the

person pulling toward the right will be a point Twelve

zero The guy pulling up one The one who doesn't

understand how war works and is really messing up the

whole shebang Yeah well he'll have y coordinate of zero

comma four right there Now we can add the x

and y components Tto find the net force Well the

net force along the x axis equals negative nine plus

twelve plus zero And along the y axis it equals

zero plus zero plus four So that gives us a

net force along the x axis of three And along

the y axis of four Now because these forces are

in a right angle to each other we can use

the pythagorean theorem toe Add them together Little pythagoras taught

the world that a squared plus b squared equals c

squared that we can plug in our numbers and find

that the net force Vector is five and while we

don't have the exact direction we know that the forces

are being applied to the north and to the east

Well in our coordinate playing the force will be in

the upper right quadrant All of this tells us that

the answer is c right there five in northeast when

we're dealing with vector edition diagrams are always helpful so

draw a little sketch on the test to make it

clear There's No reason to struggle harder than you need

that's True in physics or in tug of war sometimes

the best way to win Yeah just let go No