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Q4.16: NCERT Physics - Part 1 LAWS OF MOTION 4.16 Solution: Two masses 8 kg and 12 kg are connected at the two ends of a…

⚠️ Common Exam Traps & Conceptual Pitfalls

Students frequently apply the formula $T = m(g-a)$ to both masses, ignoring that the lighter mass accelerates upward (requiring $T = m_1(g+a)$) while the heavier mass accelerates downward (requiring $T = m_2(g-a)$). Always verify the direction of acceleration for each specific mass to determine the correct sign in the tension equation.

Two masses 8 kg and 12 kg are connected at the two ends of a light inextensible string that goes over a frictionless pulley. Find the acceleration of the masses, and the tension in the string when the masses are released.

Step-by-Step Verified Solution

**Answer:** a = 2 m/s_, T = 96 N **Step-by-Step Explanation:** For Atwood machine:
a=(m2−m1)gm1+m2=(12−8)×108+12=4020=2 m/s2a = \frac{(m_2 - m_1)g}{m_1 + m_2} = \frac{(12 - 8) \times 10}{8 + 12} = \frac{40}{20} = 2 \text{ m/s}^2
Tension:
T=m1(g+a)=8(10+2)=96 NT = m_1(g + a) = 8(10 + 2) = 96 \text{ N}
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All Questions in this Chapter

Q4.1 Q4.2 Q4.3 Q4.4 Q4.5 Q4.6 Q4.7 Q4.8 Q4.9 Q4.10 Q4.11 Q4.12 Q4.13 Q4.14 Q4.15 Q4.16 Q4.17 Q4.18 Q4.19 Q4.20 Q4.21 Q4.22 Q4.23

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