Finding Forces & Work: 105 kg Mass Suspended by 7 m Rope

In summary: Lastly, you can use this force (and distance) to calculate the work done by the worker.In summary, using the given mass, length, and displacement, we can find the tension in the rope to be 1029 N. With this tension and the angle, we can calculate the horizontal force needed to hold the bag in a displaced position, which is 479 N. Finally, by multiplying this force with the displacement, we can find the work done by the worker to be 1437 J.
  • #1
honeyspells
3
0
::A mail bag with a mass of 105 kg is suspended by a vertical rope of length 7.00 m .

A) What horizontal force is necessary to hold the bag in a position displaced sideways a distance 3.00 m from its initial position?
Take free fall acceleration to be g = 9.80 m/s2 .

B) How much work is done by the worker in moving the bag to this position?
Take free fall acceleration to be g = 9.80 m/s2 .

m= 105 kg
y= 7 m
x= 3 m
So first I made a right triangle to find the angles, the angles I found were 25(from the vertical) and 66.

The tension in the string is 105 kg x 9.8 m/s2 right? with that I have T=1029 N

I then used 1029tan(25)= 479 N .What do I need to do to figure out ho much work is done?
tips for moving on?
 
Last edited:
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  • #2
Work is the integral of the working force over the arc length through which it acts. Have you tried calculating that?
 
  • #3
honeyspells said:
::A mail bag with a mass of 105 kg is suspended by a vertical rope of length 7.00 m .

A) What horizontal force is necessary to hold the bag in a position displaced sideways a distance 3.00 m from its initial position?
Take free fall acceleration to be g = 9.80 m/s2 .

B) How much work is done by the worker in moving the bag to this position?
Take free fall acceleration to be g = 9.80 m/s2 .

m= 105 kg
y= 7 m
x= 3 m
So first I made a right triangle to find the angles, the angles I found were 25(from the vertical) and 66.

The tension in the string is 105 kg x 9.8 m/s2 right? with that I have T=1029 N

I then used 1029tan(25)= 479 N .What do I need to do to figure out ho much work is done?
tips for moving on?
For work just take the weight of the object multiplied by its displacement, you'll probably need the angle you calculated above. Also, I think your above calculations are incorrect...
edit: not incorrect, just not what the problem is asking for
 
Last edited:
  • #4
you calculated the tension if the bag was just hanging vertically, I believe you need to calculate tension while the bag is displaced...
 
  • #5
Ok, after doing this problem it looks like you are on the right track (you've calculated the weight and the angle to the vertical). Your next step will be to use the weight and angle to calculate the tension in the rope, then use this tension (and angle) to calculate the force needed to hold the bag a certain distance from the vertical.
 

1. What is the formula for finding the force of an object suspended by a rope?

The formula for finding the force of an object suspended by a rope is F = mg, where F is the force in Newtons, m is the mass in kilograms, and g is the acceleration due to gravity (9.8 m/s²).

2. How do you calculate the work done when lifting a 105 kg mass by a 7 m rope?

The work done when lifting a 105 kg mass by a 7 m rope can be calculated by using the formula W = Fd, where W is the work done in Joules, F is the force in Newtons, and d is the distance in meters.

3. How much force is required to lift a 105 kg mass with a 7 m rope?

The force required to lift a 105 kg mass with a 7 m rope can be calculated by using the formula F = mg, where F is the force in Newtons, m is the mass in kilograms, and g is the acceleration due to gravity (9.8 m/s²).

4. Is there a limit to how much weight a 7 m rope can hold?

Yes, there is a limit to how much weight a 7 m rope can hold. The maximum weight that a rope can hold is determined by its breaking strength, which can vary depending on the material and thickness of the rope.

5. How does the length of the rope affect the amount of work done when lifting a mass?

The length of the rope does not affect the amount of work done when lifting a mass. The work done is determined by the force applied and the distance the object is lifted, regardless of the length of the rope.

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