Practicing Success

Target Exam

CUET

Subject

Physics

Chapter

Laws of Motion

Question:

A system consists of three masses m1, m2 and m3 connected by a string passing over a pulley P. The mass m1 hangs freely and m2 and m3 are on a rough horizontal table (the coefficient of friction = µ). The pulley is frictionless and of negligible mass. The downward acceleration of mass m1 is (Assume m1 = m2 = m3 = m)

Options:

\(\frac{g(1-2\mu)}{9}\)

\(\frac{2g\mu)}{3}\)

\(\frac{g(1-2\mu)}{3}\)

\(\frac{g(1-2\mu)}{2}\)

Correct Answer:

\(\frac{g(1-2\mu)}{3}\)

Explanation:

\( m_1g - T_1 = m_1a \) ---------(1)

\( T_1 - f_1 - T_2 = m_2a \) ------------(2)

\( T_3 - f_1 = m_3a \) -----------(3)

On solving above equation we get

m1 = m2 = m3 = m

mg - 2μmg = 3ma

⇒ a = \(\frac{g(1-2\mu)}{3}\)