How Does Nick's Acceleration Change When His Friend Pulls the Rope?

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In summary: What forces act on Nick now?The tension in the rope is the same, but the force exerted by the rope on the Nick + chair system is not.
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brandonp620
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Summary:: An inventive child named Nick wants to reach an apple in a tree without climbing the tree. Sitting in a chair connected to a rope that passes over a frictionless pulley (see figure below), Nick pulls on the loose end of the rope with such a force that the spring scale reads 350 N. Nick's true weight is 270 N, and the chair weighs 160 N. Nick's feet are not touching the ground. Use g=9.8 m/s^2.
a = 6.153 m/s^2
magnitude nick on chair 89.52N
Friend pulling pully: ? m/s^2

An inventive child named Nick wants to reach an apple in a tree without climbing the tree. Sitting in a chair connected to a rope that passes over a frictionless pulley (see figure below), Nick pulls on the loose end of the rope with such a force that the spring scale reads 350 N. Nick's true weight is 270 N, and the chair weighs 160 N. Nick's feet are not touching the ground. Use g=9.8 m/s^2.

Find Nick's acceleration, using upward as positive: a = 6.153 m/s^2

Find the magnitude of the force Nick exerts on the chair: 89.52N

Instead Nick hands the rope with the scale to his friend Barney, who stands on the ground. Barney pulls on the rope so that the spring scale again reads 350 N. What is Nick's acceleration now, again using upward as positive.: ? m/s^2

physics.JPG
Screenshot_20210917-132137_Samsung Notes.jpg


Not sure what changes in the last question T would still equal the same. Not sure what forces changes in the free body diagram, would deeply appreciate any help with the problem.
 
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  • #2
brandonp620 said:
Not sure what changes in the last question T would still equal the same. Not sure what forces changes in the free body diagram, would deeply appreciate any help with the problem.
The tension in the rope is the same, but the force exerted by the rope on the Nick + chair system is not. Do you see why?
 
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  • #3
brandonp620 said:
Not sure what changes in the last question T would still equal the same. Not sure what forces changes in the free body diagram, would deeply appreciate any help with the problem.
Please post your FBD for the second part.
 
  • #4
kuruman said:
The tension in the rope is the same, but the force exerted by the rope on the Nick + chair system is not. Do you see why?
I do not, It would still have the Normal force, and mg and Tension would still be in the same direction. So I'm a little lost. Would there only be one tension force?
 
  • #5
haruspex said:
Please post your FBD for the second part.
I don't have one because I'm not sure about the difference.
 
  • #6
brandonp620 said:
Would there only be one tension force?
There are still two tension forces, but what they act on is different.
brandonp620 said:
I don't have one because I'm not sure about the difference.
Think about each in turn. What forces act on Nick now? What forces act on the chair now?
 
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You’re not going to be able to do this without a free body diagram, so please show us your best shot at it. It doesn’t have to be perfect.
 

Related to How Does Nick's Acceleration Change When His Friend Pulls the Rope?

1. What is tension in physics?

Tension in physics is a force that is exerted on an object by a string, cable, or other type of rope. It is a pulling force that is transmitted through the length of the rope and can be caused by external forces such as gravity or internal forces from the object itself.

2. How is tension different from force?

Tension is a specific type of force that is exerted through a rope or string, while force can refer to any type of push or pull on an object. Tension is always directed along the length of the rope, while force can be applied in any direction.

3. What is the relationship between tension and acceleration?

The relationship between tension and acceleration is described by Newton's second law of motion, which states that the net force on an object is equal to its mass multiplied by its acceleration. In other words, the tension in a rope can cause an object to accelerate if there is a net force acting on the object in the direction of the tension.

4. How do you calculate tension in a rope?

To calculate tension in a rope, you need to know the mass of the object being pulled, the acceleration of the object, and the angle of the rope with respect to the horizontal. You can then use the formula T = mg + ma + mg(sinθ), where T is tension, m is mass, g is the acceleration due to gravity, a is the object's acceleration, and θ is the angle of the rope.

5. Can tension ever be negative?

No, tension cannot be negative. It is always a positive force that acts in the direction of the rope. If an object is being pulled in the opposite direction of the tension, the tension force will be negative in the equation, but in reality, it is still a positive force acting on the object.

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