I am lost, how do I find tension of a rope given A and M?

In summary, the weight of the bucket pulls down on the rope, causing the tension to increase and the net external force to be 0.
  • #1
Dante
3
0

Homework Statement


A rope is used to lower a 1.1 kg bucket into a well at an acceleration of 1.9 m/s2. Determine the tension in the rope (in Newtons). Assume that air resistance is negligible and the acceleration due to gravity is -9.8 m/s2. Take the positive direction to be upward.

Homework Equations


Newtons 2nd law, A=Fnet/Mnet
T= m (g-a)

The Attempt at a Solution



-1.9 m/s2 = X/1.1 = -2.09N (wrong)
1.1 (-9.8-1.9) = -12.9N (Unsure if right/wrong)

I am lost, I am suppose to use Newtons 2nd law equation but it makes no sense, please help.
 
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  • #2
Have you drawn a free body diagram? If T is pointing upward and g is pointing downward, what is the net external force on the bucket?
 
  • #3
Chestermiller said:
Have you drawn a free body diagram? If T is pointing upward and g is pointing downward, what is the net external force on the bucket?
I did draw a free body diagram, hopefully correctly. The weight would be pulling it down making the tension to pull up causing the net external force to be 0 since they cancel each other out, right? If I plugged 0 into the equation for the net force then what would I solve for, since there would be no X?
 
  • #4
Okay, so the tension and weight do not equal each other, instead they add up to equal the net force, correct? Meaning if I use that equation to find the net force, I then add the weight to it to find the tension? Meaning it would be -2.09 + 1.1kg = .99N?
 
  • #5
Let T be the upward tension, and mg be the downward force of gravity on the bucket (i.e., its weight). The net of these in the upward direction is T-mg. If a is the upward acceleration, what is Newton's second law written in terms of these parameters? In this problem, is "a" positive (upward) or negative (downward)? What does the force balance you wrote down give you for the tension in the rope?

Chet
 

FAQ: I am lost, how do I find tension of a rope given A and M?

1. What is tension in a rope?

Tension in a rope refers to the force that is applied to the rope, pulling it taut. It is the opposite force to the weight or load that is being supported by the rope.

2. How can I find the tension of a rope?

The tension of a rope can be calculated using the formula T = M x A, where T is the tension, M is the mass of the object being supported, and A is the acceleration due to gravity. This calculation assumes that the rope is not stretched or compressed.

3. What is A and M in the formula for tension?

A represents the acceleration due to gravity, which is typically 9.8 meters per second squared on Earth. M represents the mass of the object being supported by the rope.

4. What are the units for tension?

The units for tension are typically in newtons (N) or pounds (lbs), depending on the unit system being used. In the formula T = M x A, the units for T would be in newtons or pounds, M would be in kilograms (kg) or pounds (lbs), and A would be in meters per second squared (m/s²) or feet per second squared (ft/s²).

5. Can tension in a rope be negative?

No, tension in a rope cannot be negative. It is always a positive value because it is the force that is being applied to the rope, regardless of the direction.

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