Forces on an inclined plane with a pulley

In summary, the problem involves a 77.0 kg patient suspended in a raised hospital bed with a wire attached to a brace on their neck. The wire pulls parallel to the bed and the coefficients of kinetic and static friction between the patient and bed are 0.500 and 0.800, respectively. The goal is to find the lowest mass that will keep the patient stationary, taking into account the forces of gravity and static friction.
  • #1
kmerr98277
2
0

Homework Statement


A 77.0 kg patient is suspended in a raised hospital bed as shown in the figure. The wire is attached to a brace on the patient's neck and pulls parallel to the bed, and the coefficients of kinetic and static friction between the patient and the bed are 0.500 and 0.800, respectively.
P4-80.jpg

My attempt:
mg sinθ = mg sinθ
(77.0)(9.8)(sin50) = m(9.8)(sin90)
578.057 = m9.8
m = 58.985
I'm not sure if I set that up right. Also, I don't know how to factor in the friction to the equation.
 
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  • #2
kmerr98277 said:

Homework Statement


A 77.0 kg patient is suspended in a raised hospital bed as shown in the figure. The wire is attached to a brace on the patient's neck and pulls parallel to the bed, and the coefficients of kinetic and static friction between the patient and the bed are 0.500 and 0.800, respectively.
P4-80.jpg

My attempt:
mg sinθ = mg sinθ
(77.0)(9.8)(sin50) = m(9.8)(sin90)
578.057 = m9.8
m = 58.985
I'm not sure if I set that up right. Also, I don't know how to factor in the friction to the equation.
I think what the question wants is the lowest mass that keeps the patient stationary right?
Well you are missing something in your solution.. Static friction.
I think you should add the value of static friction to the right side to the incline
So the equation should be M(Patient) g sin θ = T(which equal to mg) + Us * n (equals mg cosθ)
Imagine that patient is not connected to mass. He would fall right? but what is the counter of the force here static friction... Now try to imagine that you are adding small amount of mass each time to balance out the forces. By the equation you will get the right amount of mass and the lowest

 
Last edited:

Related to Forces on an inclined plane with a pulley

1. What is an inclined plane with a pulley?

An inclined plane with a pulley is a simple machine that consists of a flat surface that is angled and a wheel with a groove, known as a pulley, that can rotate. This setup allows for the use of mechanical advantage to lift heavy objects with less force.

2. How do forces work on an inclined plane with a pulley?

There are two main forces at work on an inclined plane with a pulley: the force of gravity and the force applied to the object. The angle of the incline affects the magnitude of these forces, with a steeper incline requiring less force to lift the object. The pulley also helps to distribute the force evenly, making it easier to lift heavy objects.

3. What is the relationship between the angle of the incline and the force required?

The force required to lift an object on an inclined plane with a pulley is directly related to the angle of the incline. As the angle increases, the force required decreases. This is because the steeper incline allows for more of the force to be directed towards lifting the object, rather than pulling it along the incline.

4. What is the mechanical advantage of an inclined plane with a pulley?

The mechanical advantage of an inclined plane with a pulley is the ratio of the weight of the object being lifted to the force applied to lift it. This ratio is affected by the angle of the incline and the number of pulleys used. The greater the mechanical advantage, the less force is required to lift the object.

5. What are some real-world applications of an inclined plane with a pulley?

Inclined planes with pulleys are commonly used in various industries, such as construction, manufacturing, and transportation. They are used to lift heavy objects, such as construction materials, machinery, and goods, and are also found in everyday objects like elevators and escalators.

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