Equilibrium, toppling and sliding Quiz

1. A uniform lamina hangs freely from a point $P$ in equilibrium. What is true of its centre of mass $G$?

• A. $G$ is vertically below $P$
• B. $G$ is at the same height as $P$
• C. $G$ is at the midpoint of the longest edge
• D. $G$ is vertically above $P$

2. A uniform block 0.3 m wide and 0.8 m high rests on a rough slope. What is the value of $\tan\alpha$ at which it topples?

• A. $\frac{8}{3}$
• B. $\frac{3}{16}$
• C. $\frac{3}{4}$
• D. $\frac{3}{8}$

3. A uniform block of weight 50 N, base width 0.4 m, rests on horizontal ground. A horizontal force $P$ acts at a height of 0.8 m above the ground. What value of $P$ makes it about to topple?

• A. 25 N
• B. 5 N
• C. 12.5 N
• D. 50 N

4. A block of weight 40 N rests on rough horizontal ground with $\mu=0.3$. What is the limiting friction?

• A. 120 N
• B. $\frac{40}{0.3}$ N
• C. 0.3 N
• D. 12 N

5. A block 0.5 m wide and 1.0 m high has $\mu=0.7$ with its slope. The slope is tilted gradually. What happens?

• A. It slides at $\alpha=35.0^\circ$
• B. It topples at $\alpha=26.6^\circ$
• C. It slides at $\alpha=26.6^\circ$
• D. It topples at $\alpha=35.0^\circ$