Two masses, m1 = 3.0\text{kg} and m2 = 1.0\text{kg}, hang from a string over an ideal frictionless pulley. Using g \approx 10\text{m/s}^2, what is the acceleration of the system?

5.0\text{m/s}^2 a = \dfrac{(m1 - m2)g}{m1 + m2} = \dfrac{(3.0 - 1.0)(10)}{3.0 + 1.0} = 5.0\text{m/s}^2 (heavier side descends).

Kinetic and Static Friction

AP Physics 1· difficulty 3/5

m_1 = 3.0~\text{kg}

Explanation

a = \dfrac{(m_1 - m_2)g}{m_1 + m_2} = \dfrac{(3.0 - 1.0)(10)}{3.0 + 1.0} = 5.0~\text{m/s}^2

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