Q 11-06-180JEE MainJEE Main 2020 (7 Jan, Shift 1)Easy
Three point particles of masses $1.0$ kg, $1.5$ kg and $2.5$ kg are placed at three corners of a right angle triangle of sides $4.0$ cm, $3.0$ cm and $5.0$ cm as shown in the figure. The centre of mass of the system is at a point:
Answer: (D) $0.9$ cm right and $2.0$ cm above the $1$ kg mass
Take the $1$ kg mass (at the right angle) as origin, the $1.5$ kg mass at $(3, 0)$ cm and the $2.5$ kg mass at $(0, 4)$ cm. Total mass $= 5$ kg.
$$x_{cm} = \frac{1.5\times3}{5} = 0.9\ \text{cm}, \qquad y_{cm} = \frac{2.5\times4}{5} = 2.0\ \text{cm}$$
Solution by Sreeraj P, M.Sc Physics