How would you come to the conclusion that trolley must be accelerating if you were to just analyse the trolley with the hands and ground friction being the external forces?Lnewqban said:
The magnitude of one force is greater than the opposite one; the magnitude of the resultant force is the difference.pkc111 said:
You have to assume that the teacher pushes the cart so as to keep the cart a constant distance in front. She adjusts Fteacher to keep the two accelerations the same.pkc111 said:
If we take the rope as massless then there can be no net force on it, and the tension is the same along its length. It is therefore equal to the forces applied by the two teams, so those are equal to each other.pkc111 said:
But they are not equal forces applied by the teams. That is why the question says that the system is accelerating to the right.haruspex said:
Don't confuse the forces the teams exert on each other with the force each exerts on the ground.pkc111 said:
I understand that, but to explain how it is that the forces the teams exert on each other can be the same even though they accelerate you need to consider the net force on each team (since that is what causes the acceleration).pkc111 said:
The net force on a massless object is necessarily zero; otherwise it would have infinite acceleration.pkc111 said:
For the rope, as for any object, ##F_{net}=ma##. If the rope is massless m=0, so ##F_{net}=0##. Tensions at the ends are equal. The teams exert equal forces on each other.pkc111 said:
You've lost me. How is the force the weaker team applies to the rope different to the force the weaker team applies to the rope?pkc111 said:
That is, the force the tension exerts on one team is equal and opposite to the force that team exerts on the rope; and if the rope is massless those forces are the same for the other team.haruspex said:
You don't seem to have noticed I wrote the same phrase twice, since that is how I read your question in post #13. I did not writepkc111 said:
pkc111 said:
Of course.pkc111 said:
The inviolable formula is ##F_{net}=ma##. It follows immediately that if m is zero then F is zero.pkc111 said:
As I have written repeatedly (posts #6, #10, #12, #22), the forces at the end of the rope are the same if the rope is taken as massless. As soon as you assign a mass to the rope, acceleration means the forces will be a little different.pkc111 said:
pkc111 said:
A force diagram is a visual representation of the forces acting on an object. It uses arrows to show the direction and magnitude of each force, and can help to analyze how the forces are balanced or unbalanced.
To determine if a force diagram is correct, you should check that all forces acting on the object are included and that their directions and magnitudes are accurate. You should also make sure that the forces are balanced according to Newton's Third Law of Motion.
Some common mistakes in force diagrams include forgetting to include all forces, drawing forces in the wrong direction, and drawing forces with incorrect magnitudes. It is also important to remember that forces should be drawn as vectors, with both direction and magnitude represented.
Yes, a force diagram can be used for any object, as long as there are forces acting on it. Force diagrams are commonly used in physics and engineering to analyze the motion and stability of objects.
The best way to improve your force diagram skills is through practice and understanding of the principles of forces and motion. You can also seek guidance from a teacher or tutor, and use online resources and simulations to further develop your understanding.