Centre of mass of discrete masses Quiz

1. $1$ kg is at $x=0$ and $3$ kg is at $x=4$. What is the centre of mass?

• A. $3$
• B. $2$
• C. $1$
• D. $4$

2. $2$ kg at $x=1$ and $2$ kg at $x=5$: where is the centre of mass?

• A. $2$
• B. $3$
• C. $4$
• D. $6$

3. $1$ kg at $(0,0)$ and $2$ kg at $(3,3)$. What are the coordinates of the centre of mass?

• A. $(1,1)$
• B. $(1.5,1.5)$
• C. $(3,3)$
• D. $(2,2)$

4. A light rod $AB$ of length $3$ m has $2$ kg at $A$ and $4$ kg at $B$. How far from $A$ should it be supported to balance?

• A. $1$ m
• B. $1.5$ m
• C. $2$ m
• D. $2.5$ m

5. A system of total mass $5$ kg has its centre of mass at $x=3$. A $5$ kg particle is added at $x=7$. Where is the new centre of mass?

• A. $4$
• B. $5$
• C. $6$
• D. $7$