Friction JEE physics - Friction

• A
  $3000\  \mathrm{~N}$
• B
  $4000\  \mathrm{~N}$
• C
  $5000\  \mathrm{~N}$
• ✓
  $6000 \ \mathrm{~N}$

Answer: D.

• A
  $750 \mathrm{~N}$
• B
  $500 \mathrm{~N}$
• C
  $345 \mathrm{~N}$
• ✓
  $250 \mathrm{~N}$

Answer: D.

• ✓
  $\left(1-\frac{1}{n^2}\right)$
• B
  $\frac{1}{1-n^2}$
• C
  $\sqrt{\left(1-\frac{1}{n^2}\right)}$
• D
  $\sqrt{\frac{1}{1-n^2}}$

Answer: A.

A block $A$ with mass $100 \mathrm{~kg}$ is resting on another block $B$ of mass $200 \mathrm{~kg}$. As shown in figure a horizontal rope tied to a wall holds it. The coefficient of friction between $A$ and $B$ is $0.2$ while coefficient of friction between $B$ and the ground is $0.3.$ The minimum required force $F$ to start moving $B$ will be

• A
  $900 \mathrm{~N}$
• B
  $100 \mathrm{~N}$
• ✓
  $1100 \mathrm{~N}$
• D
  $1200 \mathrm{~N}$

Answer: C.

• A
  $2.50 \mathrm{~m} / \mathrm{s}^2$
• B
  $5.00 \mathrm{~m} / \mathrm{s}^2$
• ✓
  $7.4 \mathrm{~m} / \mathrm{s}^2$
• D
  $8.66 \mathrm{~m} / \mathrm{s}^2$

Answer: C.