_WCLN - Physics - Forces 4 - Net Force
This video follows Forces 1-3. What is net force? This tutorial is about adding forces to get a net force. It includes net force, free body diagrams (FBD), and force addition.
#physics #forces #netforce #fbd
0:00at this point we've learned a lot about forces forces are pushes or pulls on an
0:07object forces can cause changes in motion forces can speed up an object or
0:15slow it down forces can be contact forces such as applied forces or
0:23friction forces but forces can also be non-contact such as gravity or magnetic
0:31for Asus forces are most commonly measured in Newtons and one Newton is
0:39about the way to the medium Apple pushing forces also called compression
0:46can be measured using a floor scale while pulling forces also called tension
0:54can be measured using a spring scale in this tutorial we're going to learn about
1:01net force that is the addition of more than one force so consider that you
1:09could push on an object with a force of one hundred and and if your friend can
1:15push with a force of sixty Newton's then how much force can you both apply to the
1:22box if you both push well first let's draw little picture of the object with
1:29both forces being represented by arrows in the direction of the force the 100
1:37numero that's your push is shown to the right here then we have your friends 16
1:45you narrow and we'll try it a little bit shortages show that it is a smaller
1:50force and so here we are with the object and the forces on it and we call this
1:57little sketch a free body diagram which we often just radius FBD
2:05free body diagram is used to make a situation look really simple so now
2:12let's consider what
2:13is happening here by referring to a free body diagram now since you're both
2:19pushing in the same direction that is the force arrows on the free body
2:24diagram are both in the same direction we could just add the forces together
2:30and determine that the box receives a total applied force of one hundred and
2:37sixteen Newton's to the right so we'd say that the net force on the object is
2:45one hundred and sixty Newton's to the rate they change in motion of the box
2:50would be as if there was just a single force of one hundred and sixty Newton's
2:57to the right
3:01another example what if your friend was pushing this time in the opposite
3:06direction of you so they're pushing on the other side of the box so you're
3:10pushing with a hundred and to the right and they're pushing the other way with
3:1516 to the left then what happens
3:19well let's first run free body diagram and this time the airless would be going
3:26in opposite directions
3:28your force is going to the rate again but in this case your friends force is
3:33to the left a little bit smaller again so your sources are opposing each other
3:40so they wouldn't add the same anymore with your friends force would be tense
3:46laying out part of your source so you're pushing harder so then met applied force
3:52experienced by the box is your source 100 Newton's minus your friends for 16
4:01IANS which equals forty Newton's to the right so we would say that then met
4:09forests on the object is 40 mutants to the right that change in motion of the
4:16object would be as if there was just a single source of forty Newton's to the
4:22right
4:24one more example what if you were pushing to the rates and your friend was
4:29pushing to the left but we also had a frictional force that is maybe your
4:35object was on a rough concrete floor making it hard to move the friction
4:40force in this case is 40 Newton's to the left
4:45opposing the motion of the box so let's first maker free body diagram so in this
4:52case we have your force pushing right hundred Newtons and then your friends
4:57force pushing left 16 innings now the frictional force is opposing the motion
5:02and so it's going left at forty Newtons and seek insured along the surface here
5:08where it's apply now adding up for a net forest well we have one hundred and
5:14going rights minus sixty Newton's going left and then another 40 news going left
5:22which we have to subtract so we add all that up and we have 100 miners 60-40 and
5:31that equals zero so what does that mean a net force of 0 is almost like having
5:37no force acting on the object at all the emotion doesn't change we would say that
5:45the forces in this case our balance that is they all add up to zero or that the
5:53net force is zero which is a very interesting case
6:00in this tutorial we learn how to consider more than one for us on a