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Question
Two balls are thrown simultaneously in air. The acceleration of the centre of mass of the two balls while in air
Options
depends on the direction of the motion of the balls
depends on the masses of the two balls
depends on the speeds of the two balls
is equal to g.
Solution
is equal to g
The acceleration of the centre of mass of two balls having masses m1 and m2 is given by
\[a_{cm} = \frac{m_1 \vec{a}_1 + m_2 \vec{a}_2}{m_1 + m_2}\]
\[ = \frac{m_1 g + m_2 g}{m_1 + m_2}\]
\[ = g\]
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