# Plotting the graph of Friction Force vs. time (Laws of motion)

• SpectraPhy09
In summary, the conversation discusses the forces and motion involved in a system of two blocks connected by a string. The maximum forces acting on each block are determined by their masses and the coefficient of friction. When the force applied is between 0 and 5N, there is no motion between the blocks and the tension in the string is 0. As the force applied increases beyond 5N, the string becomes taut and the tension and friction between the blocks come into play. The acceleration of each block is dependent on the forces acting on it, and the graphs for the force and tension are different before and after t=5. The conversation also considers the state of the string and the forces acting on the 2kg block when
SpectraPhy09
Homework Statement
Coefficient of friction between all the surfaces in 0.5. Which diagram would describe the friction between the ground and the 2Kg Block when f = t N is applied on the 2kg Block? It is given that the string is not taut initially.(Plz check the the diagram in the image attached). take g= 10m/s^2
Relevant Equations
F = ma
F(friction) = μmg
F.B.D Of first block
(I have shown only the horizontal Forces)

f1(max) = μ (1kg)(g) = 0.5 * 10 = 5N
F.B.D Of the second Block

f2(max) = μ (3kg)(g) = 15N

Now the string will become taut and the tension will start acting when f = t = 5N
But for 0<f<5N there will be no motion between the 1 kg and the 2 kg block so the f2=0
but when f > 5N the string will become taut and the friction the Tension will start will acting now suppose the acceleration of the 1 kg block in left direction is a1 then,
(1)a1 = f - T - f1
and suppose the acceleration od the 2kg block is a2 then,
(2)a2 = f1 - f2 - T
But how will be plot the graph between f2 and t after t=5 since we do not know the T ension neither the acceleration of the block.
Also in the option for 0<t<5 there is different graph that mine.
Plz can someone help me how to solve this problem ahead?

#### Attachments

• Laws Of motion_Doubt_Full syllabus test-1.png
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SpectraPhy09 said:
But for 0<f<5N there will be no motion between the 1 kg and the 2 kg block so the f2=0
If f2=0 and the string is not taut, what stops the pair of blocks moving left?
SpectraPhy09 said:
suppose the acceleration od the 2kg block is a2
If the 2kg block is moving, what is the state of the string? Assume it is inextensible.
SpectraPhy09 said:
(2)a2 = f1 - f2 - T
You have drawn f1 and f2 acting in the same direction on the 2kg block.

## 1. What is the purpose of plotting the graph of Friction Force vs. time?

The purpose of plotting this graph is to visually represent the relationship between friction force and time, as described by the laws of motion. This can help to better understand and analyze the behavior of objects in motion and the forces acting on them.

## 2. What are the laws of motion that govern this graph?

The laws of motion that govern this graph are Newton's laws of motion. These include the law of inertia, the law of acceleration, and the law of action and reaction. These laws explain how objects behave in motion and the forces that act upon them, including friction force.

## 3. How is the slope of the graph related to the coefficient of friction?

The slope of the graph represents the rate of change of friction force with respect to time. This slope is directly related to the coefficient of friction, which is a measure of the resistance to motion between two surfaces in contact. A steeper slope indicates a higher coefficient of friction, and vice versa.

## 4. What factors can affect the shape of the graph?

Several factors can affect the shape of the graph, including the type of surface, the mass of the object, and the force applied to the object. The roughness of the surface and the presence of any lubricants can also impact the shape of the graph.

## 5. How can the graph be used to determine the kinetic friction coefficient?

The kinetic friction coefficient can be determined by finding the slope of the graph at any point where the object is in motion. This slope represents the ratio of friction force to normal force, which is equal to the kinetic friction coefficient. Therefore, by calculating the slope, the kinetic friction coefficient can be determined.

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