Three blocks of masses 2 kg, 3 kg and 5 kg are connected to each other with light string and are then placed on a smooth frictionless surface. The system is pulled with force F from side of the lighter mass so that it moves an acceleraton of `1 ms^(2), T_(1)` and `T_(2)` denote the tension in the other strings. The value of F is:

Options

A. 30 N
B. 20 N
C. 10 N
D. 40 N

Answer

C

Explanation

Equations of motons are
for 2 kg block, `F - T_(1) = 2a`……(i)
for 3 kg block , `T_(1) - T_(2) = 3a`……….(ii)
For 5 kg block
putting the value of `T_(2)` in eq. (ii)
`therefore T_(1) - 5a = 3a rArr T_(1) = 8a` [Putting in eq.(i)]
`F - 8a = 2a rArr F = 10 N (a = 1 m//s^(2))`