Tension and acceleration of a sled?

AI Thread Summary
To determine the minimum rope tension required to move a sled with a mass of 336 kg, the static friction coefficient is 0.579. The discussion suggests starting by calculating the force needed to overcome static friction using the formula Ff,s = μs * Fg. After finding this force, it can be divided between two ropes pulling at an angle of 25° from each other, with each rope making a 30.1° angle with the horizontal. The approach involves treating the problem in two parts: first finding the force at angle θ, then distributing that force between the two ropes. Understanding these steps is crucial for solving the problem effectively.
TheNeezoMan
Messages
4
Reaction score
1

Homework Statement


A heavy sled is being pulled by two people as shown in the figure. The coefficient of static friction between the sled and the ground is μs = 0.579, and the kinetic friction coefficient is μk = 0.435. The combined mass of the sled and its load is m = 336 kg. The ropes are separated by an angle φ = 25°, and they make an angle θ = 30.1° with the horizontal. Assuming both ropes pull equally hard, what is the minimum rope tension required to get the sled moving?

Sled Diagram.jpeg

Homework Equations


T-mg=ma (I think...)

The Attempt at a Solution



So, say person 1 exerts tension T1 and person 2 T2, so T1=T2=T ...So they both exert a force of 2T.

Untitled.png

I am not even sure if this diagram is right?
I also think wemust must find Ff,s = μs * Fg

I don't know where to go from here or I if this is where I should even be

[/B]
 
Physics news on Phys.org
I think you'll want to start by seeing what single force applied at angle θ = 30.1° will get the sled moving. After that you can deal with how to divide that force between two ropes with the given angular spread.
 
  • Like
Likes TheNeezoMan
If I am going to divide an angle wouldn't it be φ = 25°?
 
TheNeezoMan said:
If I am going to divide an angle wouldn't it be φ = 25°?
Dealing with φ will come later. Treat this as two separate problems: 1) Find the force required to move the sled if the force is applied to the sled at angle θ; 2) Take the force from (1) and split it between two ropes separated by angle φ.
 
  • Like
Likes TheNeezoMan
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
Thread 'Voltmeter readings for this circuit with switches'
TL;DR Summary: I would like to know the voltmeter readings on the two resistors separately in the picture in the following cases , When one of the keys is closed When both of them are opened (Knowing that the battery has negligible internal resistance) My thoughts for the first case , one of them must be 12 volt while the other is 0 The second case we'll I think both voltmeter readings should be 12 volt since they are both parallel to the battery and they involve the key within what the...
Back
Top