Question

Three blocks of masses ml = 10 kg, m² = 20 kg are connected by strings on smooth horizontal surface and pulled by a force of 60 N. Find the acceleration of the system and frictions in the string.

Answer 1

All the blocks more with common acceleration a under the force 

F = 60 N. 

F = (m₁ + m₂ + m₃ )a 

a = \(\frac{F}{(m_1 + m_2 + m_3)}\)a = 1 m/s² 

to determine, T₁ →Free body diagram of m₁.

T₁ = m₁ a = 10 x 1 = 10 N 

to determine, T₂ →Free body diagram of m₃

F – T₂ = m₃ a 

Solving, we get T₂ = 30 N