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Tension HW Problem

  • Thread starter TikiPost10
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This is the question: At an airport, luggage is unloaded from a plane into the three cars of a luggage carrier. The acceleration of the carrier is .12 m/s2, and friction is negligible. The coupling bars have negligible mass. By how much would the tension in each of the coupling bars A, B, and C change if 39 kg of luggage were removed from car 2 and placed in (a) car 1 and (b) car 3? If the tension changes, specifiy whether it increases or decreases.

In setting the problem up, do you calculate say, Tension A with the mg of Car 1, Tension B with the mg of Car 2, etc. and then add those totals OR do you add all the x-components of the tensions and then all the y-components?
 

OlderDan

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TikiPost10 said:
This is the question: At an airport, luggage is unloaded from a plane into the three cars of a luggage carrier. The acceleration of the carrier is .12 m/s2, and friction is negligible. The coupling bars have negligible mass. By how much would the tension in each of the coupling bars A, B, and C change if 39 kg of luggage were removed from car 2 and placed in (a) car 1 and (b) car 3? If the tension changes, specifiy whether it increases or decreases.

In setting the problem up, do you calculate say, Tension A with the mg of Car 1, Tension B with the mg of Car 2, etc. and then add those totals OR do you add all the x-components of the tensions and then all the y-components?
The best way to approach problems of this sort is to look at each accelerating object separately, recognizing that they have a common acceleration. You can write an F = ma equation for each car, where in two of the three cases F is the difference between two tensions. See if you can write the three equations and take it from there.

It does turn out that each tension equals the mass of all cars trailing each bar times the acceleration.
 

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