Man pulling a cube on a rough surface

In summary, the man, with a mass of 70 kg and a static coefficient of friction of 0.6, pulls a box at an angle of 100 degrees. The kinetic coefficient of friction between the box and the floor is 0.3. The maximum mass of the box that the man can pull is approximately 164.87 kg.
  • #1
Karol
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Homework Statement


A man of mass 70[kg] pules a box at an angle 100. the static coefficient of friction between his legs and the floor is 0.6 and the kinetic coefficient between the box and the floor is 0.3
What's the maximum's box's mass

Homework Equations


Friction: f=μN

The Attempt at a Solution


The horizontal force the man can apply:
$$70\cdot 9.81\cdot 0.6=412.02=F\cdot \cos 10^0\rightarrow F=418.38$$
The vertical component of F raises the box: ##F\cdot \sin 10^0=418.02\cdot\sin 10^0=72.65##
the force needed to pull the box:
$$(mg-F\cdot \sin 10^0)0.3=412.02\rightarrow (mg-72.65)0.3=412.02\rightarrow m=147.4[kg]$$
It should be 164.85
 

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  • #2
The vertical component of F does more than just that !
 
  • #3
The vertical component also presses down on the man:
$$\left\{ \begin{array}{l} (mg-F\cdot \sin10^0)0.3=(70\cdot g+F\cdot \sin10^0)0.6 \\ F\cdot \cos10^0=(mg-F\cdot \sin10^0)0.3 \end{array} \right. $$
$$\rightarrow F=467.88,\ m=164.87\ \surd$$
 

1. What is the purpose of pulling a cube on a rough surface?

The purpose of pulling a cube on a rough surface is to study the effects of friction and surface roughness on the movement and stability of objects.

2. How does the roughness of the surface affect the movement of the cube?

The roughness of the surface can increase the friction between the cube and the surface, making it more difficult to pull the cube. It can also cause the cube to vibrate or slide in unpredictable ways, making it harder to control its movement.

3. What factors can affect the amount of friction between the cube and the rough surface?

The amount of friction between the cube and the rough surface can be affected by the weight and shape of the cube, the texture and composition of the surface, and the force applied to pull the cube.

4. How can friction be reduced when pulling the cube on a rough surface?

Friction can be reduced by using a lubricant on the surface, choosing a smoother surface, or reducing the weight of the cube. Additionally, pulling the cube at a slower and more controlled speed can also help to reduce friction.

5. What are the potential real-world applications of studying a man pulling a cube on a rough surface?

Studying the movement of a cube on a rough surface can have real-world applications in fields such as engineering, transportation, and sports. It can help engineers design more efficient and stable structures, improve the performance of vehicles on different terrains, and enhance the techniques used in sports such as skiing and skateboarding.

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