Q28 of 42 Page 34

Two masses of 5 kg and 3 kg are suspended with help of massless inextensible strings as shown in Fig. 5.6. Calculate T1 and T2 when whole system is going upwards with acceleration = 2 m s2 (use g = 9.8 m s-2).


In such questions, we first draw the free body diagrams. From the above diagram, we write the Newton’s equation for each mass.
Here, M = 5 kg
 m = 3 kg

a = 2 m s-2


Therefore, the equations are:



Substituting the values of m, M, a and g and solving the above equations gives us:


T1 = 94.4 N


T2 = 35.4 N


More from this chapter

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26

A mass of 2kg is suspended with thread AB (Fig. 5.5). Thread CD of the same type is attached to the other end of 2 kg mass. Lower thread is pulled gradually, harder and harder in the downward direction so as to apply force on AB. Which of the threads will break and why?


 27

In the above given problem if the lower thread is pulled with a jerk, what happens?

 29

Block A of weight 100 N rests on a frictionless inclined plane of slope angle 30° (Fig. 5.7). A flexible cord attached to A passes over a frictionless pulley and is connected to block B of weight W. Find the weight W for which the system is in equilibrium.


 30

A block of mass M is held against a rough vertical wall by pressing it with a finger. If the coefficient of friction between the block and the wall is μ and the acceleration due to gravity is g, calculate the minimum force required to be applied by the finger to hold the block against the wall?