Q128 / 160 · TS EAMCET 2024 (09 May Shift 1) · Physics
A solid sphere rolls down without slipping from the top of an inclined plane of height 28 m and angle of inclination $30^{\circ}$. The velocity of the sphere, when it reaches the bottom of the plane is (Acceleration due to gravity $=10 \mathrm{~ms}^{-2}$ )
- Correct answerA$20 \mathrm{~ms}^{-1}$
- B$28 \mathrm{~ms}^{-1}$
- C$10 \mathrm{~ms}^{-1}$
- D$14 \mathrm{~ms}^{-1}$
Solution
Velocity of sphere rolls down without slipping
$v=\sqrt{\frac{2 \mathrm{gh}}{1+\frac{\mathrm{k}^2}{\mathrm{R}^2}}}=\sqrt{\frac{2 \times 10 \times 28}{1+\frac{2}{5}}}=\sqrt{\frac{2 \times 10 \times 28 \times 5}{7}}=20 \mathrm{~m} / \mathrm{s}$
Hence, the correct answer is option: 'A'.