Calculating Tension Using Work Energy Theorem

In summary, the question involves an object on a rough ramp connected to a hanging object via a pulley. Using Newton's Law of motion, the tension on the 17kg object was found to be 330N while the tension on the 99kg object was 796.75N. The question now is to find the tension on the 17kg object using the work energy theorem. However, since the forces and accelerations were already calculated, the use of the theorem may seem artificial.
  • #1
JHLee
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Hi, I have a homework and I kind of stuck on it. Here is the question:

A 17 kg object on a rough ramp (coefficient of friction = 0.35N, ramp's angle = 25 degrees) is connected to a vertically hanging object via a pulley with I = 23 kg m^2 and the radius is 0.25m. The hanging object had weight 971N. The hanging object dropped 7 meters. Find the tension on the 17 kg object using work energy theorem.

So far I've found the actual weight of the hanging object which is approximately 99kg. The velocity 4.95m/s, the acceleration 1.75m/s^2, and angular velocity 19.8m/s.

When I use the Newton's Law of motion, I could find the tension of the 17kg object equal to 330N while for the 99kg equal to 796.75N so the angular acceleration would be approximately 5 m/s^2. But the thing is, I need to find the tension of the 17kg using the work energy theorem as well but I don't know how.

Please help me? Thanks!
 
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  • #2
JHLee said:
found the actual weight of the hanging object
Mass
JHLee said:
angular velocity 19.8m/s.
Wrong units.
JHLee said:
find the tension of the 17kg using the work energy theorem
The question is a bit strange. You had to work with forces and accelerations because of the residual velocity. But having found that, you have the KE, so you could write out the energy balance for the 17kg object to find the work done against friction.
Rather an artificial "use" of the theorem, though.
 

What is "Work done by tension"?

"Work done by tension" refers to the amount of energy transferred by a tension force acting on an object. This occurs when the object is being moved or displaced by the tension force.

How is work done by tension calculated?

The work done by tension can be calculated using the equation W = Fd, where W is the work done, F is the magnitude of the tension force, and d is the displacement of the object in the direction of the tension force.

What are some examples of work done by tension?

Some examples of work done by tension include pulling a sled across the snow, lifting a bucket of water using a rope, and swinging on a rope swing.

Can work done by tension be negative?

Yes, work done by tension can be negative if the tension force is acting in the opposite direction of the displacement of the object. This means that the tension force is doing work against the movement of the object, resulting in a negative amount of work done.

How does the angle of the tension force affect the work done by tension?

The angle of the tension force affects the work done by tension because it determines the component of the force that is acting in the direction of the displacement of the object. A larger angle means that less of the tension force is contributing to the work done, resulting in a smaller amount of work done.

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