• Support PF! Buy your school textbooks, materials and every day products via PF Here!

A mail bag with a mass of 105kg is suspended by a vertical rope of length 7.00m .

::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:
2,087
514
Work is the integral of the working force over the arc length through which it acts. Have you tried calculating that?
 
346
3
::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:
346
3
you calculated the tension if the bag was just hanging vertically, I believe you need to calculate tension while the bag is displaced...
 
346
3
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.
 

Want to reply to this thread?

"A mail bag with a mass of 105kg is suspended by a vertical rope of length 7.00m ." You must log in or register to reply here.

Related Threads for: A mail bag with a mass of 105kg is suspended by a vertical rope of length 7.00m .

  • Posted
Replies
6
Views
5K
Replies
1
Views
6K
Replies
2
Views
2K
Replies
2
Views
1K
Replies
1
Views
2K
  • Posted
Replies
11
Views
2K
Replies
1
Views
5K

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top