Rotational Motion Question 151
Question: Three masses are placed on the x-axis: 300 g at origin, 500g at $x=40cm$ and 400g at$x=70cm$ . The distance of the centre of mass from the origin is
Options:
A) 40cm
B) 45cm
C) 50cm
D) 30cm
Show Answer
Answer:
Correct Answer: A
Solution:
[a]
$X _{cm}=\frac{m _{1}x _{1}+m _{2}x _{2}+m _{3}x _{3}}{m _{1}+m _{2}+m _{3}}$
$X _{cm}=\frac{300\times (0)+500(40)+400\times 70}{300+500+400}$
$X _{cm}=\frac{500\times 40+400\times 70}{1200}=40cm$
