Question

What are the co-ordinates of the centre of mass of the three-particle system shown in fig.?

• A. $x=1.1 \,m , y=1.3 \,m$
• B. $x=0.7 \,m , y=0.8\, m$
• C. $x=0.5 \,m , y=0.6 \,m$
• D. $x=0 \,m , y=3 \,m$

Answer 1

Answer: (A)

$ x_{ cm }=\frac{(3 \,kg )(0\, m )+(8 \,kg )(1 \,m )+(4 \,kg )(2 \,m )}{(3\, kg +8 \,kg +4 \,kg )}$
$=\frac{16\, kg\, m }{15 \,kg } \approx 1.1 \,m$
$y_{ cm }=\frac{(3 kg )(0 m )+(8 kg )(2 m )+(4 kg )(1 m )}{(3 kg +8 kg +4 \,kg )}$
$=\frac{20\, kg\, m }{15 \,kg } \approx 1.3 \,m$