A lamp hangs vertically from a cord in elevator which is descending with an downward acceleration of a=2m/s2.the tension in the cord T=10.0N . what is the mass m of the lamp?

Asked by Rohan Astik | 27th Sep, 2013, 09:47: PM

Expert Answer:

The elevator is descending downwards with an acceleration a. The weight of lamp is also in the downward direction. The tension T acts in the vertical direction on the thread with which lamp is hung.
 
Thus, the balance equation of forces on the lamp is:
 
mg - T = ma
mg - ma = T
m(g - a) = T
Thus, m = T/(g - a) = 10/7.8 = 1.28 kg

Answered by Romal Bhansali | 28th Sep, 2013, 03:35: PM

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