question_answer

                A lift of mass 1000 kg is moving upwards with an acceleration of \[1\,m/{{s}^{2}}\]. The tension developed in the string, which is connected to lift is: \[(g=9.8\,m/{{s}^{2}})\]                                                                                 

A)                 9800 N                 

B)                 10800 N               

C)                 11000 N               

D)                 10000 N

Correct Answer: B

Solution :

                Key Idea: The tension in the string during upward motion increases from weight of life due to its upward acceleration.                                 When lift moves upward with same acceleration then                 T ? mg = ma                 or            T = m (g + a)                 Given \[m=1000kg,\,\,a=1\,\,m/{{s}^{2}},\,g=9.8\,m/{{s}^{2}}\]                 Thus,      T = 1000 (9.8+1)                 \[=1000\,\times 10.8\]                 = 10800 N