Mechanics Problem: Pushing a heavy desk across a floor

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In summary, the conversation is about studying first year physics at university and solving a problem involving forces. The suggested approach is to create free body diagrams and use vector addition to find the acceleration. Additional resources are also provided for assistance.
  • #1
naushaan
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Homework Statement
hey guys, I'm a bit stuck on this question for my assignment:
Relevant Equations
Two students are trying to move a heavy desk, mass = 48 kg, across a smooth floor by applying forces
F1 = 20.4 N and F2 = 14.7 N in a horizontal direction. They have put smooth cloth under the feet of the desk to stop it scratching the highly polished timber floor. Initially they apply the forces at right angles to each other. (Assume the desk moves in the xy-plane.) (Assume F1 lies along the positive x-axis and F2 lies in the positive y direction.)

(a) Find the acceleration of the desk. Write the acceleration as a vector. (Assume F1 lies along the positive x-axis and F2 lies in the positive y direction.)
(b) If they push so that the angle between the direction of the forces is 60°, what is the acceleration of the desk? (Assume F1 lies along the positive x-axis and F2 lies in the positive y direction.)
(c) If the forces are parallel, what is the acceleration of the desk? (Assume F1 lies along the positive x-axis.)
(d)If they are anti-parallel, what is the acceleration of the desk? (Assume F1 lies along the positive x-axis.)

Would really appreciate any help!
.
 
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  • #2
What work have you done so far?
Any schematic with magnitudes and directions of forces as described in the problem?
What are you studying now?
 
  • #3
i'm not sure where to start!
 
  • #4
What are you studying now?
 
  • #5
First year physics at university
 
  • #6
naushaan said:
First year physics at university
In this course, can you provide an example of something that they have taught you?
 
  • #7
naushaan said:
First year physics at university

Congratulations! :smile:
The problem is asking you about the acceleration the desk reaches under the influence of several combinations of forces.
You know that the magnitude of that acceleration is directly proportional to the vector force that results from adding the vector force exerted by each person pushing the desk.
In order to facilitate that vectorial addition (or subtraction), you should create an imaginary system of x-y coordinates.
 
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  • #8
naushaan said:
i'm not sure where to start!
Where you should always start with mechanics problems: free body diagrams.
 
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  • #9
thank you for your help!
 
  • #10

Related to Mechanics Problem: Pushing a heavy desk across a floor

1. How much force is needed to push a heavy desk across a floor?

The amount of force needed to push a heavy desk across a floor depends on a few factors, such as the weight of the desk, the type of surface the desk is being pushed on, and the coefficient of friction between the desk and the floor. Generally, the heavier the desk and the higher the coefficient of friction, the more force will be needed to push it.

2. What is the best way to push a heavy desk across a floor?

The best way to push a heavy desk across a floor is to use proper body mechanics. This includes keeping your back straight, using your leg muscles to push instead of your back, and keeping the desk close to your body. It is also helpful to have another person assist with pushing, if possible.

3. How can I reduce the amount of force needed to push a heavy desk across a floor?

One way to reduce the amount of force needed to push a heavy desk across a floor is to use a lubricant, such as oil or wax, on the bottom of the desk. This will reduce the friction between the desk and the floor, making it easier to push. Additionally, using a dolly or other wheeled device can also make pushing the desk easier.

4. Is it possible to push a heavy desk across a carpeted floor?

Yes, it is possible to push a heavy desk across a carpeted floor, but it may require more force than pushing it across a smooth, hard surface. This is because the carpet creates more friction, making it more difficult to move the desk. Using a dolly or lubricant can help make pushing the desk across a carpeted floor easier.

5. Are there any safety precautions I should take when pushing a heavy desk across a floor?

Yes, there are a few safety precautions you should take when pushing a heavy desk across a floor. First, make sure to use proper body mechanics to avoid strain or injury. It is also important to clear the path of any obstacles or tripping hazards. If the desk is particularly heavy, it may be necessary to have multiple people assist with pushing to avoid injury or damage to the desk or floor.

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